diff --git a/package.json b/package.json
index 46bc55b0245..c95e75ee5f8 100644
--- a/package.json
+++ b/package.json
@@ -8,11 +8,13 @@
     "postinstall": "lerna bootstrap",
     "publish": "tasks/release.sh",
     "start": "node packages/react-scripts/scripts/start.js",
-    "test": "node packages/react-scripts/scripts/test.js --env=jsdom"
+    "test": "node packages/react-scripts/scripts/test.js --env=jsdom",
+    "format": "prettier --trailing-comma es5 --single-quote --write 'packages/*/*.js' 'packages/*/!(node_modules)/**/*.js'"
   },
   "devDependencies": {
     "eslint": "3.16.1",
     "lerna": "2.0.0-beta.38",
-    "lerna-changelog": "^0.2.3"
+    "lerna-changelog": "^0.2.3",
+    "prettier": "^0.21.0"
   }
 }
diff --git a/packages/babel-preset-react-app/index.js b/packages/babel-preset-react-app/index.js
index 8236c64b54c..bba6e3fdb4b 100644
--- a/packages/babel-preset-react-app/index.js
+++ b/packages/babel-preset-react-app/index.js
@@ -16,21 +16,30 @@ const plugins = [
   // The following two plugins use Object.assign directly, instead of Babel's
   // extends helper. Note that this assumes `Object.assign` is available.
   // { ...todo, completed: true }
-  [require.resolve('babel-plugin-transform-object-rest-spread'), {
-    useBuiltIns: true
-  }],
+  [
+    require.resolve('babel-plugin-transform-object-rest-spread'),
+    {
+      useBuiltIns: true,
+    },
+  ],
   // Transforms JSX
-  [require.resolve('babel-plugin-transform-react-jsx'), {
-    useBuiltIns: true
-  }],
+  [
+    require.resolve('babel-plugin-transform-react-jsx'),
+    {
+      useBuiltIns: true,
+    },
+  ],
   // Polyfills the runtime needed for async/await and generators
-  [require.resolve('babel-plugin-transform-runtime'), {
-    helpers: false,
-    polyfill: false,
-    regenerator: true,
-    // Resolve the Babel runtime relative to the config.
-    moduleName: path.dirname(require.resolve('babel-runtime/package'))
-  }]
+  [
+    require.resolve('babel-plugin-transform-runtime'),
+    {
+      helpers: false,
+      polyfill: false,
+      regenerator: true,
+      // Resolve the Babel runtime relative to the config.
+      moduleName: path.dirname(require.resolve('babel-runtime/package')),
+    },
+  ],
 ];
 
 // This is similar to how `env` works in Babel:
@@ -42,9 +51,11 @@ const plugins = [
 var env = process.env.BABEL_ENV || process.env.NODE_ENV;
 if (env !== 'development' && env !== 'test' && env !== 'production') {
   throw new Error(
-    'Using `babel-preset-react-app` requires that you specify `NODE_ENV` or '+
-    '`BABEL_ENV` environment variables. Valid values are "development", ' +
-    '"test", and "production". Instead, received: ' + JSON.stringify(env) + '.'
+    'Using `babel-preset-react-app` requires that you specify `NODE_ENV` or ' +
+      '`BABEL_ENV` environment variables. Valid values are "development", ' +
+      '"test", and "production". Instead, received: ' +
+      JSON.stringify(env) +
+      '.'
   );
 }
 
@@ -59,7 +70,7 @@ if (env === 'development' || env === 'test') {
     // Adds component stack to warning messages
     require.resolve('babel-plugin-transform-react-jsx-source'),
     // Adds __self attribute to JSX which React will use for some warnings
-    require.resolve('babel-plugin-transform-react-jsx-self')
+    require.resolve('babel-plugin-transform-react-jsx-self'),
   ]);
 }
 
@@ -67,46 +78,55 @@ if (env === 'test') {
   module.exports = {
     presets: [
       // ES features necessary for user's Node version
-      [require('babel-preset-env').default, {
-        targets: {
-          node: 'current',
+      [
+        require('babel-preset-env').default,
+        {
+          targets: {
+            node: 'current',
+          },
         },
-      }],
+      ],
       // JSX, Flow
-      require.resolve('babel-preset-react')
+      require.resolve('babel-preset-react'),
     ],
     plugins: plugins.concat([
       // Compiles import() to a deferred require()
-      require.resolve('babel-plugin-dynamic-import-node')
-    ])
+      require.resolve('babel-plugin-dynamic-import-node'),
+    ]),
   };
 } else {
   module.exports = {
     presets: [
       // Latest stable ECMAScript features
-      [require.resolve('babel-preset-env'), {
-        targets: {
-          // React parses on ie 9, so we should too
-          ie: 9,
-          // We currently minify with uglify
-          // Remove after https://github.com/mishoo/UglifyJS2/issues/448
-          uglify: true
+      [
+        require.resolve('babel-preset-env'),
+        {
+          targets: {
+            // React parses on ie 9, so we should too
+            ie: 9,
+            // We currently minify with uglify
+            // Remove after https://github.com/mishoo/UglifyJS2/issues/448
+            uglify: true,
+          },
+          // Disable polyfill transforms
+          useBuiltIns: false,
         },
-        // Disable polyfill transforms
-        useBuiltIns: false
-      }],
+      ],
       // JSX, Flow
-      require.resolve('babel-preset-react')
+      require.resolve('babel-preset-react'),
     ],
     plugins: plugins.concat([
       // function* () { yield 42; yield 43; }
-      [require.resolve('babel-plugin-transform-regenerator'), {
-        // Async functions are converted to generators by babel-preset-latest
-        async: false
-      }],
+      [
+        require.resolve('babel-plugin-transform-regenerator'),
+        {
+          // Async functions are converted to generators by babel-preset-latest
+          async: false,
+        },
+      ],
       // Adds syntax support for import()
       require.resolve('babel-plugin-syntax-dynamic-import'),
-    ])
+    ]),
   };
 
   if (env === 'production') {
diff --git a/packages/create-react-app/createReactApp.js b/packages/create-react-app/createReactApp.js
index 7e51179b5ab..da9250d4d71 100755
--- a/packages/create-react-app/createReactApp.js
+++ b/packages/create-react-app/createReactApp.js
@@ -8,7 +8,7 @@
  */
 'use strict';
 
-const validateProjectName = require("validate-npm-package-name");
+const validateProjectName = require('validate-npm-package-name');
 const chalk = require('chalk');
 const commander = require('commander');
 const fs = require('fs-extra');
@@ -31,31 +31,50 @@ const program = commander
     projectName = name;
   })
   .option('--verbose', 'print additional logs')
-  .option('--scripts-version <alternative-package>', 'use a non-standard version of react-scripts')
+  .option(
+    '--scripts-version <alternative-package>',
+    'use a non-standard version of react-scripts'
+  )
   .allowUnknownOption()
   .on('--help', () => {
     console.log(`    Only ${chalk.green('<project-directory>')} is required.`);
     console.log();
-    console.log(`    A custom ${chalk.cyan('--scripts-version')} can be one of:`);
+    console.log(
+      `    A custom ${chalk.cyan('--scripts-version')} can be one of:`
+    );
     console.log(`      - a specific npm version: ${chalk.green('0.8.2')}`);
-    console.log(`      - a custom fork published on npm: ${chalk.green('my-react-scripts')}`);
-    console.log(`      - a .tgz archive: ${chalk.green('https://mysite.com/my-react-scripts-0.8.2.tgz')}`);
-    console.log(`    It is not needed unless you specifically want to use a fork.`);
+    console.log(
+      `      - a custom fork published on npm: ${chalk.green('my-react-scripts')}`
+    );
+    console.log(
+      `      - a .tgz archive: ${chalk.green('https://mysite.com/my-react-scripts-0.8.2.tgz')}`
+    );
+    console.log(
+      `    It is not needed unless you specifically want to use a fork.`
+    );
     console.log();
-    console.log(`    If you have any problems, do not hesitate to file an issue:`);
-    console.log(`      ${chalk.cyan('https://github.com/facebookincubator/create-react-app/issues/new')}`);
+    console.log(
+      `    If you have any problems, do not hesitate to file an issue:`
+    );
+    console.log(
+      `      ${chalk.cyan('https://github.com/facebookincubator/create-react-app/issues/new')}`
+    );
     console.log();
   })
   .parse(process.argv);
 
 if (typeof projectName === 'undefined') {
   console.error('Please specify the project directory:');
-  console.log(`  ${chalk.cyan(program.name())} ${chalk.green('<project-directory>')}`);
+  console.log(
+    `  ${chalk.cyan(program.name())} ${chalk.green('<project-directory>')}`
+  );
   console.log();
   console.log('For example:');
   console.log(`  ${chalk.cyan(program.name())} ${chalk.green('my-react-app')}`);
   console.log();
-  console.log(`Run ${chalk.cyan(`${program.name()} --help`)} to see all options.`);
+  console.log(
+    `Run ${chalk.cyan(`${program.name()} --help`)} to see all options.`
+  );
   process.exit(1);
 }
 
@@ -68,11 +87,19 @@ function printValidationResults(results) {
 }
 
 const hiddenProgram = new commander.Command()
-  .option('--internal-testing-template <path-to-template>', '(internal usage only, DO NOT RELY ON THIS) ' +
-    'use a non-standard application template')
-  .parse(process.argv)
+  .option(
+    '--internal-testing-template <path-to-template>',
+    '(internal usage only, DO NOT RELY ON THIS) ' +
+      'use a non-standard application template'
+  )
+  .parse(process.argv);
 
-createApp(projectName, program.verbose, program.scriptsVersion, hiddenProgram.internalTestingTemplate);
+createApp(
+  projectName,
+  program.verbose,
+  program.scriptsVersion,
+  hiddenProgram.internalTestingTemplate
+);
 
 function createApp(name, verbose, version, template) {
   const root = path.resolve(name);
@@ -81,20 +108,20 @@ function createApp(name, verbose, version, template) {
   checkAppName(appName);
   fs.ensureDirSync(name);
   if (!isSafeToCreateProjectIn(root)) {
-    console.log(`The directory ${chalk.green(name)} contains files that could conflict.`);
+    console.log(
+      `The directory ${chalk.green(name)} contains files that could conflict.`
+    );
     console.log('Try using a new directory name.');
     process.exit(1);
   }
 
-  console.log(
-    `Creating a new React app in ${chalk.green(root)}.`
-  );
+  console.log(`Creating a new React app in ${chalk.green(root)}.`);
   console.log();
 
   const packageJson = {
     name: appName,
     version: '0.1.0',
-    private: true
+    private: true,
   };
   fs.writeFileSync(
     path.join(root, 'package.json'),
@@ -108,7 +135,7 @@ function createApp(name, verbose, version, template) {
 
 function shouldUseYarn() {
   try {
-    execSync('yarnpkg --version', {stdio: 'ignore'});
+    execSync('yarnpkg --version', { stdio: 'ignore' });
     return true;
   } catch (e) {
     return false;
@@ -121,10 +148,7 @@ function install(useYarn, dependencies, verbose, isOnline) {
     let args;
     if (useYarn) {
       command = 'yarnpkg';
-      args = [
-        'add',
-        '--exact',
-      ];
+      args = ['add', '--exact'];
       if (!isOnline) {
         args.push('--offline');
       }
@@ -135,7 +159,6 @@ function install(useYarn, dependencies, verbose, isOnline) {
         console.log(chalk.yellow('Falling back to the local Yarn cache.'));
         console.log();
       }
-
     } else {
       checkNpmVersion();
       command = 'npm';
@@ -146,11 +169,11 @@ function install(useYarn, dependencies, verbose, isOnline) {
       args.push('--verbose');
     }
 
-    const child = spawn(command, args, {stdio: 'inherit'});
+    const child = spawn(command, args, { stdio: 'inherit' });
     child.on('close', code => {
       if (code !== 0) {
         reject({
-          command: `${command} ${args.join(' ')}`
+          command: `${command} ${args.join(' ')}`,
         });
         return;
       }
@@ -168,10 +191,9 @@ function run(root, appName, version, verbose, originalDirectory, template) {
   const useYarn = shouldUseYarn();
   getPackageName(packageToInstall)
     .then(packageName => checkIfOnline(useYarn).then(isOnline => ({
-        isOnline: isOnline,
-        packageName: packageName,
-      })
-    ))
+      isOnline: isOnline,
+      packageName: packageName,
+    })))
     .then(info => {
       const isOnline = info.isOnline;
       const packageName = info.packageName;
@@ -180,7 +202,9 @@ function run(root, appName, version, verbose, originalDirectory, template) {
       );
       console.log();
 
-      return install(useYarn, allDependencies, verbose, isOnline).then(() => packageName);
+      return install(useYarn, allDependencies, verbose, isOnline).then(
+        () => packageName
+      );
     })
     .then(packageName => {
       checkNodeVersion(packageName);
@@ -204,7 +228,7 @@ function run(root, appName, version, verbose, originalDirectory, template) {
       console.log();
       console.log('Aborting installation.');
       if (reason.command) {
-        console.log(`  ${chalk.cyan(reason.command)} has failed.`)
+        console.log(`  ${chalk.cyan(reason.command)} has failed.`);
       } else {
         console.log(chalk.red('Unexpected error. Please report it as a bug:'));
         console.log(reason);
@@ -213,14 +237,21 @@ function run(root, appName, version, verbose, originalDirectory, template) {
 
       // On 'exit' we will delete these files from target directory.
       const knownGeneratedFiles = [
-        'package.json', 'npm-debug.log', 'yarn-error.log', 'yarn-debug.log', 'node_modules'
+        'package.json',
+        'npm-debug.log',
+        'yarn-error.log',
+        'yarn-debug.log',
+        'node_modules',
       ];
       const currentFiles = fs.readdirSync(path.join(root));
       currentFiles.forEach(file => {
         knownGeneratedFiles.forEach(fileToMatch => {
           // This will catch `(npm-debug|yarn-error|yarn-debug).log*` files
           // and the rest of knownGeneratedFiles.
-          if ((fileToMatch.match(/.log/g) && file.indexOf(fileToMatch) === 0) || file === fileToMatch) {
+          if (
+            (fileToMatch.match(/.log/g) && file.indexOf(fileToMatch) === 0) ||
+            file === fileToMatch
+          ) {
             console.log(`Deleting generated file... ${chalk.cyan(file)}`);
             fs.removeSync(path.join(root, file));
           }
@@ -229,7 +260,9 @@ function run(root, appName, version, verbose, originalDirectory, template) {
       const remainingFiles = fs.readdirSync(path.join(root));
       if (!remainingFiles.length) {
         // Delete target folder if empty
-        console.log(`Deleting ${chalk.cyan(`${appName} /`)} from ${chalk.cyan(path.resolve(root, '..'))}`);
+        console.log(
+          `Deleting ${chalk.cyan(`${appName} /`)} from ${chalk.cyan(path.resolve(root, '..'))}`
+        );
         process.chdir(path.resolve(root, '..'));
         fs.removeSync(path.join(root));
       }
@@ -267,7 +300,7 @@ function getTemporaryDirectory() {
               // Callback might throw and fail, since it's a temp directory the
               // OS will clean it up eventually...
             }
-          }
+          },
         });
       }
     });
@@ -276,39 +309,50 @@ function getTemporaryDirectory() {
 
 function extractStream(stream, dest) {
   return new Promise((resolve, reject) => {
-    stream.pipe(unpack(dest, err => {
-      if (err) {
-        reject(err);
-      } else {
-        resolve(dest);
-      }
-    }));
+    stream.pipe(
+      unpack(dest, err => {
+        if (err) {
+          reject(err);
+        } else {
+          resolve(dest);
+        }
+      })
+    );
   });
 }
 
 // Extract package name from tarball url or path.
 function getPackageName(installPackage) {
   if (installPackage.indexOf('.tgz') > -1) {
-    return getTemporaryDirectory().then(obj => {
-      let stream;
-      if (/^http/.test(installPackage)) {
-        stream = hyperquest(installPackage);
-      } else {
-        stream = fs.createReadStream(installPackage);
-      }
-      return extractStream(stream, obj.tmpdir).then(() => obj);
-    }).then(obj => {
-      const packageName = require(path.join(obj.tmpdir, 'package.json')).name;
-      obj.cleanup();
-      return packageName;
-    }).catch(err => {
-      // The package name could be with or without semver version, e.g. react-scripts-0.2.0-alpha.1.tgz
-      // However, this function returns package name only without semver version.
-      console.log(`Could not extract the package name from the archive: ${err.message}`);
-      const assumedProjectName = installPackage.match(/^.+\/(.+?)(?:-\d+.+)?\.tgz$/)[1];
-      console.log(`Based on the filename, assuming it is "${chalk.cyan(assumedProjectName)}"`);
-      return Promise.resolve(assumedProjectName);
-    });
+    return getTemporaryDirectory()
+      .then(obj => {
+        let stream;
+        if (/^http/.test(installPackage)) {
+          stream = hyperquest(installPackage);
+        } else {
+          stream = fs.createReadStream(installPackage);
+        }
+        return extractStream(stream, obj.tmpdir).then(() => obj);
+      })
+      .then(obj => {
+        const packageName = require(path.join(obj.tmpdir, 'package.json')).name;
+        obj.cleanup();
+        return packageName;
+      })
+      .catch(err => {
+        // The package name could be with or without semver version, e.g. react-scripts-0.2.0-alpha.1.tgz
+        // However, this function returns package name only without semver version.
+        console.log(
+          `Could not extract the package name from the archive: ${err.message}`
+        );
+        const assumedProjectName = installPackage.match(
+          /^.+\/(.+?)(?:-\d+.+)?\.tgz$/
+        )[1];
+        console.log(
+          `Based on the filename, assuming it is "${chalk.cyan(assumedProjectName)}"`
+        );
+        return Promise.resolve(assumedProjectName);
+      });
   } else if (installPackage.indexOf('git+') === 0) {
     // Pull package name out of git urls e.g:
     // git+https://github.com/mycompany/react-scripts.git
@@ -316,7 +360,9 @@ function getPackageName(installPackage) {
     return Promise.resolve(installPackage.match(/([^\/]+)\.git(#.*)?$/)[1]);
   } else if (installPackage.indexOf('@') > 0) {
     // Do not match @scope/ when stripping off @version or @tag
-    return Promise.resolve(installPackage.charAt(0) + installPackage.substr(1).split('@')[0]);
+    return Promise.resolve(
+      installPackage.charAt(0) + installPackage.substr(1).split('@')[0]
+    );
   }
   return Promise.resolve(installPackage);
 }
@@ -333,10 +379,12 @@ function checkNpmVersion() {
     return;
   }
   console.log(chalk.yellow('It looks like you are using npm 2.'));
-  console.log(chalk.yellow(
-    'We suggest using npm 3 or Yarn for faster install times ' +
-    'and less disk space usage.'
-  ));
+  console.log(
+    chalk.yellow(
+      'We suggest using npm 3 or Yarn for faster install times ' +
+        'and less disk space usage.'
+    )
+  );
   console.log();
 }
 
@@ -356,8 +404,8 @@ function checkNodeVersion(packageName) {
     console.error(
       chalk.red(
         'You are running Node %s.\n' +
-        'Create React App requires Node %s or higher. \n' +
-        'Please update your version of Node.'
+          'Create React App requires Node %s or higher. \n' +
+          'Please update your version of Node.'
       ),
       process.version,
       packageJson.engines.node
@@ -369,7 +417,9 @@ function checkNodeVersion(packageName) {
 function checkAppName(appName) {
   const validationResult = validateProjectName(appName);
   if (!validationResult.validForNewPackages) {
-    console.error(`Could not create a project called ${chalk.red(`"${appName}"`)} because of npm naming restrictions:`);
+    console.error(
+      `Could not create a project called ${chalk.red(`"${appName}"`)} because of npm naming restrictions:`
+    );
     printValidationResults(validationResult.errors);
     printValidationResults(validationResult.warnings);
     process.exit(1);
@@ -383,12 +433,10 @@ function checkAppName(appName) {
     console.error(
       chalk.red(
         `We cannot create a project called ${chalk.green(appName)} because a dependency with the same name exists.\n` +
-        `Due to the way npm works, the following names are not allowed:\n\n`
-      ) +
-      chalk.cyan(
-        allDependencies.map(depName => `  ${depName}`).join('\n')
+          `Due to the way npm works, the following names are not allowed:\n\n`
       ) +
-      chalk.red('\n\nPlease choose a different project name.')
+        chalk.cyan(allDependencies.map(depName => `  ${depName}`).join('\n')) +
+        chalk.red('\n\nPlease choose a different project name.')
     );
     process.exit(1);
   }
@@ -398,9 +446,7 @@ function makeCaretRange(dependencies, name) {
   const version = dependencies[name];
 
   if (typeof version === 'undefined') {
-    console.error(
-      chalk.red(`Missing ${name} dependency in package.json`)
-    );
+    console.error(chalk.red(`Missing ${name} dependency in package.json`));
     process.exit(1);
   }
 
@@ -421,18 +467,14 @@ function fixDependencies(packageName) {
   const packageJson = require(packagePath);
 
   if (typeof packageJson.dependencies === 'undefined') {
-    console.error(
-      chalk.red('Missing dependencies in package.json')
-    );
+    console.error(chalk.red('Missing dependencies in package.json'));
     process.exit(1);
   }
 
   const packageVersion = packageJson.dependencies[packageName];
 
   if (typeof packageVersion === 'undefined') {
-    console.error(
-      chalk.red(`Unable to find ${packageName} in package.json`)
-    );
+    console.error(chalk.red(`Unable to find ${packageName} in package.json`));
     process.exit(1);
   }
 
@@ -451,10 +493,16 @@ function fixDependencies(packageName) {
 // https://github.com/facebookincubator/create-react-app/pull/368#issuecomment-243446094
 function isSafeToCreateProjectIn(root) {
   const validFiles = [
-    '.DS_Store', 'Thumbs.db', '.git', '.gitignore', '.idea', 'README.md', 'LICENSE', 'web.iml'
+    '.DS_Store',
+    'Thumbs.db',
+    '.git',
+    '.gitignore',
+    '.idea',
+    'README.md',
+    'LICENSE',
+    'web.iml',
   ];
-  return fs.readdirSync(root)
-    .every(file => validFiles.indexOf(file) >= 0);
+  return fs.readdirSync(root).every(file => validFiles.indexOf(file) >= 0);
 }
 
 function checkIfOnline(useYarn) {
@@ -464,7 +512,7 @@ function checkIfOnline(useYarn) {
     return Promise.resolve(true);
   }
 
-  return new Promise((resolve) => {
+  return new Promise(resolve => {
     dns.resolve('registry.yarnpkg.com', err => {
       resolve(err === null);
     });
diff --git a/packages/create-react-app/index.js b/packages/create-react-app/index.js
index 412d4baaaa8..19a3ff09fd4 100755
--- a/packages/create-react-app/index.js
+++ b/packages/create-react-app/index.js
@@ -44,9 +44,11 @@ var currentNodeVersion = process.versions.node;
 if (currentNodeVersion.split('.')[0] < 4) {
   console.error(
     chalk.red(
-      'You are running Node ' + currentNodeVersion + '.\n' +
-      'Create React App requires Node 4 or higher. \n' +
-      'Please update your version of Node.'
+      'You are running Node ' +
+        currentNodeVersion +
+        '.\n' +
+        'Create React App requires Node 4 or higher. \n' +
+        'Please update your version of Node.'
     )
   );
   process.exit(1);
diff --git a/packages/eslint-config-react-app/index.js b/packages/eslint-config-react-app/index.js
index 44066a6eacf..1c6911cb2de 100644
--- a/packages/eslint-config-react-app/index.js
+++ b/packages/eslint-config-react-app/index.js
@@ -30,7 +30,7 @@ module.exports = {
     commonjs: true,
     es6: true,
     jest: true,
-    node: true
+    node: true,
   },
 
   parserOptions: {
@@ -39,20 +39,18 @@ module.exports = {
     ecmaFeatures: {
       jsx: true,
       generators: true,
-      experimentalObjectRestSpread: true
-    }
+      experimentalObjectRestSpread: true,
+    },
   },
 
   settings: {
-    'import/ignore': [
-      'node_modules'
-    ],
+    'import/ignore': ['node_modules'],
     'import/extensions': ['.js'],
     'import/resolver': {
       node: {
-        extensions: ['.js', '.json']
-      }
-    }
+        extensions: ['.js', '.json'],
+      },
+    },
   },
 
   rules: {
@@ -89,15 +87,18 @@ module.exports = {
     'no-labels': ['warn', { allowLoop: false, allowSwitch: false }],
     'no-lone-blocks': 'warn',
     'no-loop-func': 'warn',
-    'no-mixed-operators': ['warn', {
-      groups: [
-        ['&', '|', '^', '~', '<<', '>>', '>>>'],
-        ['==', '!=', '===', '!==', '>', '>=', '<', '<='],
-        ['&&', '||'],
-        ['in', 'instanceof']
-      ],
-      allowSamePrecedence: false
-    }],
+    'no-mixed-operators': [
+      'warn',
+      {
+        groups: [
+          ['&', '|', '^', '~', '<<', '>>', '>>>'],
+          ['==', '!=', '===', '!==', '>', '>=', '<', '<='],
+          ['&&', '||'],
+          ['in', 'instanceof'],
+        ],
+        allowSamePrecedence: false,
+      },
+    ],
     'no-multi-str': 'warn',
     'no-native-reassign': 'warn',
     'no-negated-in-lhs': 'warn',
@@ -110,11 +111,7 @@ module.exports = {
     'no-octal-escape': 'warn',
     'no-redeclare': 'warn',
     'no-regex-spaces': 'warn',
-    'no-restricted-syntax': [
-      'warn',
-      'LabeledStatement',
-      'WithStatement',
-    ],
+    'no-restricted-syntax': ['warn', 'LabeledStatement', 'WithStatement'],
     'no-script-url': 'warn',
     'no-self-assign': 'warn',
     'no-self-compare': 'warn',
@@ -128,27 +125,36 @@ module.exports = {
     'no-restricted-globals': ['error', 'event'],
     'no-unexpected-multiline': 'warn',
     'no-unreachable': 'warn',
-    'no-unused-expressions': ['warn', {
-      'allowShortCircuit': true,
-      'allowTernary': true
-    }],
+    'no-unused-expressions': [
+      'warn',
+      {
+        allowShortCircuit: true,
+        allowTernary: true,
+      },
+    ],
     'no-unused-labels': 'warn',
-    'no-unused-vars': ['warn', {
-      vars: 'local',
-      varsIgnorePattern: '^_',
-      args: 'none',
-      ignoreRestSiblings: true,
-    }],
+    'no-unused-vars': [
+      'warn',
+      {
+        vars: 'local',
+        varsIgnorePattern: '^_',
+        args: 'none',
+        ignoreRestSiblings: true,
+      },
+    ],
     'no-use-before-define': ['warn', 'nofunc'],
     'no-useless-computed-key': 'warn',
     'no-useless-concat': 'warn',
     'no-useless-constructor': 'warn',
     'no-useless-escape': 'warn',
-    'no-useless-rename': ['warn', {
-      ignoreDestructuring: false,
-      ignoreImport: false,
-      ignoreExport: false,
-    }],
+    'no-useless-rename': [
+      'warn',
+      {
+        ignoreDestructuring: false,
+        ignoreImport: false,
+        ignoreExport: false,
+      },
+    ],
     'no-with': 'warn',
     'no-whitespace-before-property': 'warn',
     'operator-assignment': ['warn', 'always'],
@@ -159,15 +165,19 @@ module.exports = {
     'unicode-bom': ['warn', 'never'],
     'use-isnan': 'warn',
     'valid-typeof': 'warn',
-    'no-restricted-properties': ['error', {
-      object: 'require',
-      property: 'ensure',
-      message: 'Please use import() instead. More info: https://webpack.js.org/guides/code-splitting-import/#dynamic-import'
-    }, {
-      object: 'System',
-      property: 'import',
-      message: 'Please use import() instead. More info: https://webpack.js.org/guides/code-splitting-import/#dynamic-import'
-    }],
+    'no-restricted-properties': [
+      'error',
+      {
+        object: 'require',
+        property: 'ensure',
+        message: 'Please use import() instead. More info: https://webpack.js.org/guides/code-splitting-import/#dynamic-import',
+      },
+      {
+        object: 'System',
+        property: 'import',
+        message: 'Please use import() instead. More info: https://webpack.js.org/guides/code-splitting-import/#dynamic-import',
+      },
+    ],
 
     // https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/
 
@@ -203,10 +213,13 @@ module.exports = {
     'react/jsx-equals-spacing': ['warn', 'never'],
     'react/jsx-no-duplicate-props': ['warn', { ignoreCase: true }],
     'react/jsx-no-undef': 'error',
-    'react/jsx-pascal-case': ['warn', {
-      allowAllCaps: true,
-      ignore: [],
-    }],
+    'react/jsx-pascal-case': [
+      'warn',
+      {
+        allowAllCaps: true,
+        ignore: [],
+      },
+    ],
     'react/jsx-uses-react': 'warn',
     'react/jsx-uses-vars': 'warn',
     'react/no-danger-with-children': 'warn',
@@ -226,6 +239,6 @@ module.exports = {
     // https://github.com/gajus/eslint-plugin-flowtype
     'flowtype/define-flow-type': 'warn',
     'flowtype/require-valid-file-annotation': 'warn',
-    'flowtype/use-flow-type': 'warn'
-  }
+    'flowtype/use-flow-type': 'warn',
+  },
 };
diff --git a/packages/react-dev-utils/FileSizeReporter.js b/packages/react-dev-utils/FileSizeReporter.js
index 08273673f92..a0db0684f4a 100644
--- a/packages/react-dev-utils/FileSizeReporter.js
+++ b/packages/react-dev-utils/FileSizeReporter.js
@@ -33,7 +33,7 @@ function printFileSizesAfterBuild(webpackStats, previousSizeMap) {
         folder: path.join('build', path.dirname(asset.name)),
         name: path.basename(asset.name),
         size: size,
-        sizeLabel: filesize(size) + (difference ? ' (' + difference + ')' : '')
+        sizeLabel: filesize(size) + (difference ? ' (' + difference + ')' : ''),
       };
     });
   assets.sort((a, b) => b.size - a.size);
@@ -88,12 +88,15 @@ function measureFileSizesBeforeBuild(buildFolder) {
       if (!err && fileNames) {
         sizes = fileNames
           .filter(fileName => /\.(js|css)$/.test(fileName))
-          .reduce((memo, fileName) => {
-            var contents = fs.readFileSync(fileName);
-            var key = removeFileNameHash(buildFolder, fileName);
-            memo[key] = gzipSize(contents);
-            return memo;
-          }, {});
+          .reduce(
+            (memo, fileName) => {
+              var contents = fs.readFileSync(fileName);
+              var key = removeFileNameHash(buildFolder, fileName);
+              memo[key] = gzipSize(contents);
+              return memo;
+            },
+            {}
+          );
       }
       resolve({
         root: buildFolder,
diff --git a/packages/react-dev-utils/InterpolateHtmlPlugin.js b/packages/react-dev-utils/InterpolateHtmlPlugin.js
index 07558f47830..ac1d3e9967d 100644
--- a/packages/react-dev-utils/InterpolateHtmlPlugin.js
+++ b/packages/react-dev-utils/InterpolateHtmlPlugin.js
@@ -25,7 +25,8 @@ class InterpolateHtmlPlugin {
 
   apply(compiler) {
     compiler.plugin('compilation', compilation => {
-      compilation.plugin('html-webpack-plugin-before-html-processing',
+      compilation.plugin(
+        'html-webpack-plugin-before-html-processing',
         (data, callback) => {
           // Run HTML through a series of user-specified string replacements.
           Object.keys(this.replacements).forEach(key => {
diff --git a/packages/react-dev-utils/ansiHTML.js b/packages/react-dev-utils/ansiHTML.js
index 27a514e01d0..1144fec5e65 100644
--- a/packages/react-dev-utils/ansiHTML.js
+++ b/packages/react-dev-utils/ansiHTML.js
@@ -34,15 +34,15 @@ var base0E = 'a71d5d'; // Keywords, Storage, Selector, Markup Italic, Diff Chang
 var colors = {
   reset: [base05, 'transparent'],
   black: base05,
-  red: base08, /* marker, bg-invalid */
-  green: base0B, /* string */
-  yellow: base08, /* capitalized, jsx_tag, punctuator */
+  red: base08 /* marker, bg-invalid */,
+  green: base0B /* string */,
+  yellow: base08 /* capitalized, jsx_tag, punctuator */,
   blue: base0C,
-  magenta: base0C, /* regex */
-  cyan: base0E, /* keyword */
-  gray: base03, /* comment, gutter */
+  magenta: base0C /* regex */,
+  cyan: base0E /* keyword */,
+  gray: base03 /* comment, gutter */,
   lightgrey: base01,
-  darkgrey: base03
+  darkgrey: base03,
 };
 
 var anserMap = {
@@ -56,20 +56,19 @@ var anserMap = {
   'ansi-bright-red': 'red',
   'ansi-red': 'red',
   'ansi-bright-magenta': 'magenta',
-  'ansi-magenta': 'magenta'
+  'ansi-magenta': 'magenta',
 };
 
 function ansiHTML(txt) {
   var arr = new Anser().ansiToJson(txt, {
-    use_classes: true
+    use_classes: true,
   });
 
   var result = '';
   var open = false;
   for (var index = 0; index < arr.length; ++index) {
     var c = arr[index];
-    var content = c.content,
-        fg = c.fg;
+    var content = c.content, fg = c.fg;
 
     var contentParts = content.split('\n');
     for (var _index = 0; _index < contentParts.length; ++_index) {
diff --git a/packages/react-dev-utils/clearConsole.js b/packages/react-dev-utils/clearConsole.js
index 74336284723..05ab28c44d2 100644
--- a/packages/react-dev-utils/clearConsole.js
+++ b/packages/react-dev-utils/clearConsole.js
@@ -10,7 +10,9 @@
 'use strict';
 
 function clearConsole() {
-  process.stdout.write(process.platform === 'win32' ? '\x1Bc' : '\x1B[2J\x1B[3J\x1B[H');
+  process.stdout.write(
+    process.platform === 'win32' ? '\x1Bc' : '\x1B[2J\x1B[3J\x1B[H'
+  );
 }
 
 module.exports = clearConsole;
diff --git a/packages/react-dev-utils/crashOverlay.js b/packages/react-dev-utils/crashOverlay.js
index d92e793ac18..4f58e927f3c 100644
--- a/packages/react-dev-utils/crashOverlay.js
+++ b/packages/react-dev-utils/crashOverlay.js
@@ -68,15 +68,18 @@ var css = [
   '  .cra-container {',
   '    width: calc(1170px - 6em);',
   '  }',
-  '}'
+  '}',
 ].join('\n');
 
 var overlayStyle = {
   position: 'fixed',
   'box-sizing': 'border-box',
-  top: '1em', left: '1em',
-  bottom: '1em', right: '1em',
-  width: 'calc(100% - 2em)', height: 'calc(100% - 2em)',
+  top: '1em',
+  left: '1em',
+  bottom: '1em',
+  right: '1em',
+  width: 'calc(100% - 2em)',
+  height: 'calc(100% - 2em)',
   'border-radius': '3px',
   'background-color': lightGray,
   padding: '4rem',
@@ -88,7 +91,7 @@ var overlayStyle = {
   'overflow-x': 'hidden',
   'word-break': 'break-all',
   'box-shadow': '0 0 6px 0 rgba(0, 0, 0, 0.5)',
-  'line-height': 1.5
+  'line-height': 1.5,
 };
 
 var hintsStyle = {
@@ -96,12 +99,12 @@ var hintsStyle = {
   'margin-top': '-3em',
   'margin-bottom': '3em',
   'text-align': 'right',
-  color: darkGray
+  color: darkGray,
 };
 
 var hintStyle = {
   padding: '0.5em 1em',
-  cursor: 'pointer'
+  cursor: 'pointer',
 };
 
 var closeButtonStyle = {
@@ -111,55 +114,55 @@ var closeButtonStyle = {
   cursor: 'pointer',
   position: 'absolute',
   right: 0,
-  top: 0
+  top: 0,
 };
 
 var additionalStyle = {
   'margin-bottom': '1.5em',
-  'margin-top': '-4em'
+  'margin-top': '-4em',
 };
 
 var headerStyle = {
   'font-size': '1.7em',
   'font-weight': 'bold',
-  color: red
+  color: red,
 };
 
 var functionNameStyle = {
   'margin-top': '1em',
-  'font-size': '1.2em'
+  'font-size': '1.2em',
 };
 
 var linkStyle = {
-  'font-size': '0.9em'
+  'font-size': '0.9em',
 };
 
 var anchorStyle = {
   'text-decoration': 'none',
-  color: darkGray
+  color: darkGray,
 };
 
 var traceStyle = {
-  'font-size': '1em'
+  'font-size': '1em',
 };
 
 var depStyle = {
-  'font-size': '1.2em'
+  'font-size': '1.2em',
 };
 
 var primaryErrorStyle = {
-  'background-color': lightRed
+  'background-color': lightRed,
 };
 
 var secondaryErrorStyle = {
-  'background-color': yellow
+  'background-color': yellow,
 };
 
 var omittedFramesStyle = {
   color: black,
   'font-size': '0.9em',
-  'margin': '1.5em 0',
-  cursor: 'pointer'
+  margin: '1.5em 0',
+  cursor: 'pointer',
 };
 
 var preStyle = {
@@ -169,25 +172,25 @@ var preStyle = {
   'margin-bottom': '0px',
   'overflow-x': 'auto',
   'font-size': '1.1em',
-  'white-space': 'pre'
+  'white-space': 'pre',
 };
 
 var toggleStyle = {
   'margin-bottom': '1.5em',
   color: darkGray,
-  cursor: 'pointer'
+  cursor: 'pointer',
 };
 
 var codeStyle = {
-  'font-family': 'Consolas, Menlo, monospace'
+  'font-family': 'Consolas, Menlo, monospace',
 };
 
 var hiddenStyle = {
-  display: 'none'
+  display: 'none',
 };
 
 var groupStyle = {
-  'margin-left': '1em'
+  'margin-left': '1em',
 };
 
 var _groupElemStyle = {
@@ -197,24 +200,24 @@ var _groupElemStyle = {
   'border-radius': '4px',
   'border-style': 'solid',
   padding: '3px 6px',
-  cursor: 'pointer'
+  cursor: 'pointer',
 };
 
 var groupElemLeft = Object.assign({}, _groupElemStyle, {
   'border-top-right-radius': '0px',
   'border-bottom-right-radius': '0px',
-  'margin-right': '0px'
+  'margin-right': '0px',
 });
 
 var groupElemRight = Object.assign({}, _groupElemStyle, {
   'border-top-left-radius': '0px',
   'border-bottom-left-radius': '0px',
-  'margin-left': '-1px'
+  'margin-left': '-1px',
 });
 
 var footerStyle = {
   'text-align': 'center',
-  color: darkGray
+  color: darkGray,
 };
 
 function applyStyles(element, styles) {
@@ -244,10 +247,8 @@ function consumeEvent(e) {
 
 function accessify(node) {
   node.setAttribute('tabindex', 0);
-  node.addEventListener('keydown', function (e) {
-    var key = e.key,
-        which = e.which,
-        keyCode = e.keyCode;
+  node.addEventListener('keydown', function(e) {
+    var key = e.key, which = e.which, keyCode = e.keyCode;
     if (key === 'Enter' || which === 13 || keyCode === 13) {
       e.preventDefault();
       e.target.click();
@@ -272,7 +273,7 @@ function renderAdditional() {
   applyStyles(group, groupStyle);
   var left = document.createElement('button');
   applyStyles(left, groupElemLeft);
-  left.addEventListener('click', function (e) {
+  left.addEventListener('click', function(e) {
     consumeEvent(e);
     switchError(-1);
   });
@@ -280,7 +281,7 @@ function renderAdditional() {
   accessify(left);
   var right = document.createElement('button');
   applyStyles(right, groupElemRight);
-  right.addEventListener('click', function (e) {
+  right.addEventListener('click', function(e) {
     consumeEvent(e);
     switchError(1);
   });
@@ -314,11 +315,13 @@ function absolutifyCode(component) {
 }
 
 function sourceCodePre(sourceLines, lineNum, columnNum) {
-  var main = arguments.length > 3 && arguments[3] !== undefined ? arguments[3] : false;
+  var main = arguments.length > 3 && arguments[3] !== undefined
+    ? arguments[3]
+    : false;
 
   var sourceCode = [];
   var whiteSpace = Infinity;
-  sourceLines.forEach(function (_ref2) {
+  sourceLines.forEach(function(_ref2) {
     var text = _ref2.text;
 
     var m = text.match(/^\s*/);
@@ -329,19 +332,23 @@ function sourceCodePre(sourceLines, lineNum, columnNum) {
       whiteSpace = 0;
     }
   });
-  sourceLines.forEach(function (_ref3) {
-    var text = _ref3.text,
-        line = _ref3.line;
+  sourceLines.forEach(function(_ref3) {
+    var text = _ref3.text, line = _ref3.line;
 
     if (isFinite(whiteSpace)) text = text.substring(whiteSpace);
     sourceCode[line - 1] = text;
   });
   sourceCode = sourceCode.join('\n');
-  var ansiHighlight = codeFrame(sourceCode, lineNum, columnNum - (isFinite(whiteSpace) ? whiteSpace : 0), {
-    forceColor: true,
-    linesAbove: CONTEXT_SIZE,
-    linesBelow: CONTEXT_SIZE
-  });
+  var ansiHighlight = codeFrame(
+    sourceCode,
+    lineNum,
+    columnNum - (isFinite(whiteSpace) ? whiteSpace : 0),
+    {
+      forceColor: true,
+      linesAbove: CONTEXT_SIZE,
+      linesBelow: CONTEXT_SIZE,
+    }
+  );
   var htmlHighlight = ansiHTML(ansiHighlight);
   var code = document.createElement('code');
   code.innerHTML = htmlHighlight;
@@ -379,7 +386,7 @@ function hintsDiv() {
   applyStyles(hints, hintsStyle);
 
   var close = createHint('×');
-  close.addEventListener('click', function () {
+  close.addEventListener('click', function() {
     unmount();
   });
   applyStyles(close, closeButtonStyle);
@@ -401,7 +408,10 @@ function frameDiv(functionName, url, internalUrl) {
   var cleanedUrl = url.replace('webpack://', '.');
 
   if (internalUrl) {
-    applyStyles(frameFunctionName, Object.assign({}, functionNameStyle, depStyle));
+    applyStyles(
+      frameFunctionName,
+      Object.assign({}, functionNameStyle, depStyle)
+    );
   } else {
     applyStyles(frameFunctionName, functionNameStyle);
   }
@@ -424,9 +434,11 @@ function frameDiv(functionName, url, internalUrl) {
 function getGroupToggle(omitsCount, omitBundle) {
   var omittedFrames = document.createElement('div');
   accessify(omittedFrames);
-  var text1 = document.createTextNode('\u25B6 ' + omitsCount + ' stack frames were collapsed.');
+  var text1 = document.createTextNode(
+    '\u25B6 ' + omitsCount + ' stack frames were collapsed.'
+  );
   omittedFrames.appendChild(text1);
-  omittedFrames.addEventListener('click', function () {
+  omittedFrames.addEventListener('click', function() {
     var hide = text1.textContent.match(/▲/);
     var list = document.getElementsByName('bundle-' + omitBundle);
     for (var index = 0; index < list.length; ++index) {
@@ -459,9 +471,11 @@ function insertBeforeBundle(parent, omitsCount, omitBundle, actionElement) {
   var div = document.createElement('div');
   accessify(div);
   div.setAttribute('name', 'bundle-' + omitBundle);
-  var text = document.createTextNode('\u25BC ' + omitsCount + ' stack frames were expanded.');
+  var text = document.createTextNode(
+    '\u25BC ' + omitsCount + ' stack frames were expanded.'
+  );
   div.appendChild(text);
-  div.addEventListener('click', function () {
+  div.addEventListener('click', function() {
     return actionElement.click();
   });
   applyStyles(div, omittedFramesStyle);
@@ -470,17 +484,25 @@ function insertBeforeBundle(parent, omitsCount, omitBundle, actionElement) {
   parent.insertBefore(div, first);
 }
 
-function traceFrame(frameSetting, frame, critical, omits, omitBundle, parentContainer, lastElement) {
+function traceFrame(
+  frameSetting,
+  frame,
+  critical,
+  omits,
+  omitBundle,
+  parentContainer,
+  lastElement
+) {
   var compiled = frameSetting.compiled;
   var functionName = frame.functionName,
-      fileName = frame.fileName,
-      lineNumber = frame.lineNumber,
-      columnNumber = frame.columnNumber,
-      scriptLines = frame.scriptLines,
-      sourceFileName = frame.sourceFileName,
-      sourceLineNumber = frame.sourceLineNumber,
-      sourceColumnNumber = frame.sourceColumnNumber,
-      sourceLines = frame.sourceLines;
+    fileName = frame.fileName,
+    lineNumber = frame.lineNumber,
+    columnNumber = frame.columnNumber,
+    scriptLines = frame.scriptLines,
+    sourceFileName = frame.sourceFileName,
+    sourceLineNumber = frame.sourceLineNumber,
+    sourceColumnNumber = frame.sourceColumnNumber,
+    sourceLines = frame.sourceLines;
 
   var url = void 0;
   if (!compiled && sourceFileName) {
@@ -501,9 +523,18 @@ function traceFrame(frameSetting, frame, critical, omits, omitBundle, parentCont
   if (!internalUrl || lastElement) {
     if (omits.value > 0) {
       var omittedFrames = getGroupToggle(omits.value, omitBundle);
-      setTimeout(function () {
-        insertBeforeBundle.apply(undefined, arguments);
-      }.bind(undefined, parentContainer, omits.value, omitBundle, omittedFrames), 1);
+      setTimeout(
+        (function() {
+          insertBeforeBundle.apply(undefined, arguments);
+        }).bind(
+          undefined,
+          parentContainer,
+          omits.value,
+          omitBundle,
+          omittedFrames
+        ),
+        1
+      );
       if (lastElement && internalUrl) {
         collapseElement = omittedFrames;
       } else {
@@ -523,10 +554,19 @@ function traceFrame(frameSetting, frame, critical, omits, omitBundle, parentCont
   var hasSource = false;
   if (!internalUrl) {
     if (compiled && scriptLines.length !== 0) {
-      elem.appendChild(sourceCodePre(scriptLines, lineNumber, columnNumber, critical));
+      elem.appendChild(
+        sourceCodePre(scriptLines, lineNumber, columnNumber, critical)
+      );
       hasSource = true;
     } else if (!compiled && sourceLines.length !== 0) {
-      elem.appendChild(sourceCodePre(sourceLines, sourceLineNumber, sourceColumnNumber, critical));
+      elem.appendChild(
+        sourceCodePre(
+          sourceLines,
+          sourceLineNumber,
+          sourceColumnNumber,
+          critical
+        )
+      );
       hasSource = true;
     }
   }
@@ -538,21 +578,23 @@ function lazyFrame(parent, factory, lIndex) {
   var fac = factory();
   if (fac == null) return;
   var hasSource = fac.hasSource,
-      elem = fac.elem,
-      collapseElement = fac.collapseElement;
+    elem = fac.elem,
+    collapseElement = fac.collapseElement;
 
   var elemWrapper = document.createElement('div');
   elemWrapper.appendChild(elem);
 
   if (hasSource) {
-    (function () {
+    (function() {
       var compiledDiv = document.createElement('div');
       accessify(compiledDiv);
       applyStyles(compiledDiv, toggleStyle);
 
       var o = frameSettings[lIndex];
-      var compiledText = document.createTextNode('View ' + (o && o.compiled ? 'source' : 'compiled'));
-      compiledDiv.addEventListener('click', function () {
+      var compiledText = document.createTextNode(
+        'View ' + (o && o.compiled ? 'source' : 'compiled')
+      );
+      compiledDiv.addEventListener('click', function() {
         if (o) o.compiled = !o.compiled;
 
         var next = lazyFrame(parent, factory, lIndex);
@@ -580,9 +622,22 @@ function traceDiv(resolvedFrames) {
   var index = 0;
   var critical = true;
   var omits = { value: 0, bundle: 1 };
-  resolvedFrames.forEach(function (frame) {
+  resolvedFrames.forEach(function(frame) {
     var lIndex = index++;
-    var elem = lazyFrame(trace, traceFrame.bind(undefined, frameSettings[lIndex], frame, critical, omits, omits.bundle, trace, index === resolvedFrames.length), lIndex);
+    var elem = lazyFrame(
+      trace,
+      traceFrame.bind(
+        undefined,
+        frameSettings[lIndex],
+        frame,
+        critical,
+        omits,
+        omits.bundle,
+        trace,
+        index === resolvedFrames.length
+      ),
+      lIndex
+    );
     if (elem == null) return;
     critical = false;
     trace.appendChild(elem);
@@ -596,16 +651,24 @@ function traceDiv(resolvedFrames) {
 function footer() {
   var div = document.createElement('div');
   applyStyles(div, footerStyle);
-  div.appendChild(document.createTextNode('This screen is visible only in development. It will not appear when the app crashes in production.'));
+  div.appendChild(
+    document.createTextNode(
+      'This screen is visible only in development. It will not appear when the app crashes in production.'
+    )
+  );
   div.appendChild(document.createElement('br'));
-  div.appendChild(document.createTextNode('Open your browser’s developer console to further inspect this error.'));
+  div.appendChild(
+    document.createTextNode(
+      'Open your browser’s developer console to further inspect this error.'
+    )
+  );
   return div;
 }
 
 function render(error, name, message, resolvedFrames) {
   dispose();
 
-  frameSettings = resolvedFrames.map(function () {
+  frameSettings = resolvedFrames.map(function() {
     return { compiled: false };
   });
 
@@ -644,7 +707,7 @@ function render(error, name, message, resolvedFrames) {
   container.appendChild(footer());
 
   // Mount
-  document.body.appendChild(overlayReference = overlay);
+  document.body.appendChild((overlayReference = overlay));
 }
 
 function dispose() {
@@ -652,7 +715,7 @@ function dispose() {
   document.body.removeChild(overlayReference);
   overlayReference = null;
   var head = getHead();
-  injectedCss.forEach(function (node) {
+  injectedCss.forEach(function(node) {
     head.removeChild(node);
   });
   injectedCss = [];
@@ -665,68 +728,95 @@ function unmount() {
 }
 
 function isInternalFile(url, sourceFileName) {
-  return url.indexOf('/~/') !== -1 || url.trim().indexOf(' ') !== -1 || !sourceFileName;
+  return url.indexOf('/~/') !== -1 ||
+    url.trim().indexOf(' ') !== -1 ||
+    !sourceFileName;
 }
 
 function renderError(index) {
   viewIndex = index;
   var _capturedErrors$index = capturedErrors[index],
-      error = _capturedErrors$index.error,
-      unhandledRejection = _capturedErrors$index.unhandledRejection,
-      resolvedFrames = _capturedErrors$index.resolvedFrames;
+    error = _capturedErrors$index.error,
+    unhandledRejection = _capturedErrors$index.unhandledRejection,
+    resolvedFrames = _capturedErrors$index.resolvedFrames;
 
   if (unhandledRejection) {
-    render(error, 'Unhandled Rejection (' + error.name + ')', error.message, resolvedFrames);
+    render(
+      error,
+      'Unhandled Rejection (' + error.name + ')',
+      error.message,
+      resolvedFrames
+    );
   } else {
     render(error, error.name, error.message, resolvedFrames);
   }
 }
 
 function crash(error) {
-  var unhandledRejection = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : false;
-  var sourceOverrides = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : [];
+  var unhandledRejection = arguments.length > 1 && arguments[1] !== undefined
+    ? arguments[1]
+    : false;
+  var sourceOverrides = arguments.length > 2 && arguments[2] !== undefined
+    ? arguments[2]
+    : [];
 
   if (module.hot) module.hot.decline();
 
-  StackTraceResolve(error, CONTEXT_SIZE).then(function (resolvedFrames) {
-    resolvedFrames = resolvedFrames.filter(function (_ref) {
-      var functionName = _ref.functionName;
-      return functionName.indexOf('__cra_proxy_console__') === -1;
-    });
-    var overrideCount = sourceOverrides.length,
+  StackTraceResolve(error, CONTEXT_SIZE)
+    .then(function(resolvedFrames) {
+      resolvedFrames = resolvedFrames.filter(function(_ref) {
+        var functionName = _ref.functionName;
+        return functionName.indexOf('__cra_proxy_console__') === -1;
+      });
+      var overrideCount = sourceOverrides.length,
         frameCount = resolvedFrames.length;
-    var frameIndex = 0;
-    for (var overrideIndex = 0; overrideIndex < overrideCount; ++overrideIndex) {
-      var tag = sourceOverrides[overrideIndex];
-      var shouldContinue = false;
-      for (; frameIndex < frameCount; ++frameIndex) {
-        var sourceFileName = resolvedFrames[frameIndex].sourceFileName;
-
-        if (sourceFileName == null) continue;
-        if (sourceFileName.indexOf('/' + tag.file) !== -1) {
-          var prevLineNumber = resolvedFrames[frameIndex].sourceLineNumber;
-          if (Math.abs(prevLineNumber - tag.lineNum) < CONTEXT_SIZE) {
-            resolvedFrames[frameIndex].sourceLineNumber = tag.lineNum;
+      var frameIndex = 0;
+      for (
+        var overrideIndex = 0;
+        overrideIndex < overrideCount;
+        ++overrideIndex
+      ) {
+        var tag = sourceOverrides[overrideIndex];
+        var shouldContinue = false;
+        for (; frameIndex < frameCount; ++frameIndex) {
+          var sourceFileName = resolvedFrames[frameIndex].sourceFileName;
+
+          if (sourceFileName == null) continue;
+          if (sourceFileName.indexOf('/' + tag.file) !== -1) {
+            var prevLineNumber = resolvedFrames[frameIndex].sourceLineNumber;
+            if (Math.abs(prevLineNumber - tag.lineNum) < CONTEXT_SIZE) {
+              resolvedFrames[frameIndex].sourceLineNumber = tag.lineNum;
+            }
+            shouldContinue = true;
+            break;
           }
-          shouldContinue = true;
-          break;
         }
+        if (shouldContinue) continue;
+        break;
       }
-      if (shouldContinue) continue;
-      break;
-    }
-    capturedErrors.push({ error: error, unhandledRejection: unhandledRejection, resolvedFrames: resolvedFrames });
-    if (overlayReference !== null) renderAdditional();
-    else {
-      renderError(viewIndex = 0);
-    }
-  }).catch(function (e) {
-    // This is another fail case (unlikely to happen)
-    // e.g. render(...) throws an error with provided arguments
-    console.log('Red box renderer error:', e);
-    unmount();
-    render(null, 'Error', 'There is an error with red box. *Please* report this (see console).', []);
-  });
+      capturedErrors.push({
+        error: error,
+        unhandledRejection: unhandledRejection,
+        resolvedFrames: resolvedFrames,
+      });
+      if (overlayReference !== null)
+        renderAdditional();
+      else {
+        renderError((viewIndex = 0));
+      }
+    })
+    .catch(function(e) {
+      // This is another fail case (unlikely to happen)
+      // e.g. render(...) throws an error with provided arguments
+      console.log('Red box renderer error:', e);
+      unmount();
+      render(
+        null,
+        'Error',
+        'There is an error with red box. *Please* report this (see console).',
+        []
+      );
+    });
 }
 
 function switchError(offset) {
@@ -737,12 +827,21 @@ function switchError(offset) {
   } catch (e) {
     console.log('Red box renderer error:', e);
     unmount();
-    render(null, 'Error', 'There is an error with red box. *Please* report this (see console).', []);
+    render(
+      null,
+      'Error',
+      'There is an error with red box. *Please* report this (see console).',
+      []
+    );
   }
 }
 
-window.onerror = function (messageOrEvent, source, lineno, colno, error) {
-  if (error == null || !(error instanceof Error) || messageOrEvent.indexOf('Script error') !== -1) {
+window.onerror = function(messageOrEvent, source, lineno, colno, error) {
+  if (
+    error == null ||
+    !(error instanceof Error) ||
+    messageOrEvent.indexOf('Script error') !== -1
+  ) {
     crash(new Error(error || messageOrEvent)); // TODO: more helpful message
   } else {
     crash(error);
@@ -766,13 +865,13 @@ var promiseHandler = function promiseHandler(event) {
 window.addEventListener('unhandledrejection', promiseHandler);
 
 var escapeHandler = function escapeHandler(event) {
-  var key = event.key,
-      keyCode = event.keyCode,
-      which = event.which;
+  var key = event.key, keyCode = event.keyCode, which = event.which;
 
   if (key === 'Escape' || keyCode === 27 || which === 27) unmount();
-  else if (key === 'ArrowLeft' || keyCode === 37 || which === 37) switchError(-1);
-  else if (key === 'ArrowRight' || keyCode === 39 || which === 39) switchError(1);
+  else if (key === 'ArrowLeft' || keyCode === 37 || which === 37)
+    switchError(-1);
+  else if (key === 'ArrowRight' || keyCode === 39 || which === 39)
+    switchError(1);
 };
 
 window.addEventListener('keydown', escapeHandler);
@@ -791,29 +890,34 @@ var proxyConsole = function proxyConsole(type) {
     var nIndex = warning.indexOf('\n');
     var message = warning;
     if (nIndex !== -1) message = message.substring(0, nIndex);
-    var stack = warning.substring(nIndex + 1).split('\n').filter(function (line) {
-      return line.indexOf('(at ') !== -1;
-    }).map(function (line) {
-      var prefix = '(at ';
-      var suffix = ')';
-      line = line.substring(line.indexOf(prefix) + prefix.length);
-      line = line.substring(0, line.indexOf(suffix));
-      var parts = line.split(/[:]/g);
-      if (parts.length !== 2) return null;
-      var file = parts[0];
-      var lineNum = Number(parts[1]);
-      if (isNaN(lineNum)) return null;
-      return { file: file, lineNum: lineNum };
-    }).filter(function (obj) {
-      return obj !== null;
-    });
+    var stack = warning
+      .substring(nIndex + 1)
+      .split('\n')
+      .filter(function(line) {
+        return line.indexOf('(at ') !== -1;
+      })
+      .map(function(line) {
+        var prefix = '(at ';
+        var suffix = ')';
+        line = line.substring(line.indexOf(prefix) + prefix.length);
+        line = line.substring(0, line.indexOf(suffix));
+        var parts = line.split(/[:]/g);
+        if (parts.length !== 2) return null;
+        var file = parts[0];
+        var lineNum = Number(parts[1]);
+        if (isNaN(lineNum)) return null;
+        return { file: file, lineNum: lineNum };
+      })
+      .filter(function(obj) {
+        return obj !== null;
+      });
     var error = void 0;
     try {
       throw new Error(message);
     } catch (e) {
       error = e;
     }
-    setTimeout(function () {
+    setTimeout(function() {
       return crash(error, false, stack);
     });
     return orig.apply(this, arguments);
@@ -823,7 +927,7 @@ var proxyConsole = function proxyConsole(type) {
 // proxyConsole('error');
 
 if (module.hot) {
-  module.hot.dispose(function () {
+  module.hot.dispose(function() {
     unmount();
     window.removeEventListener('unhandledrejection', promiseHandler);
     window.removeEventListener('keydown', escapeHandler);
diff --git a/packages/react-dev-utils/formatWebpackMessages.js b/packages/react-dev-utils/formatWebpackMessages.js
index bfee3ec5b65..098c48657e2 100644
--- a/packages/react-dev-utils/formatWebpackMessages.js
+++ b/packages/react-dev-utils/formatWebpackMessages.js
@@ -46,18 +46,15 @@ function formatMessage(message) {
     lines = [
       lines[0],
       // Clean up message because "Module not found: " is descriptive enough.
-      lines[1].replace(
-        'Cannot resolve \'file\' or \'directory\' ', ''
-      ).replace(
-        'Cannot resolve module ', ''
-      ).replace(
-        'Error: ', ''
-      ),
+      lines[1]
+        .replace("Cannot resolve 'file' or 'directory' ", '')
+        .replace('Cannot resolve module ', '')
+        .replace('Error: ', ''),
       // Skip all irrelevant lines.
       // (For some reason they only appear on the client in browser.)
       '',
-      lines[lines.length - 1] // error location is the last line
-    ]
+      lines[lines.length - 1], // error location is the last line
+    ];
   }
 
   // Cleans up syntax error messages.
@@ -108,7 +105,8 @@ function formatMessage(message) {
   // from user code generated by WebPack. For more information see
   // https://github.com/facebookincubator/create-react-app/pull/1050
   message = message.replace(
-    /^\s*at\s((?!webpack:).)*:\d+:\d+[\s\)]*(\n|$)/gm, ''
+    /^\s*at\s((?!webpack:).)*:\d+:\d+[\s\)]*(\n|$)/gm,
+    ''
   ); // at ... ...:x:y
 
   return message;
@@ -116,14 +114,14 @@ function formatMessage(message) {
 
 function formatWebpackMessages(json) {
   var formattedErrors = json.errors.map(function(message) {
-    return 'Error in ' + formatMessage(message)
+    return 'Error in ' + formatMessage(message);
   });
   var formattedWarnings = json.warnings.map(function(message) {
-    return 'Warning in ' + formatMessage(message)
+    return 'Warning in ' + formatMessage(message);
   });
   var result = {
     errors: formattedErrors,
-    warnings: formattedWarnings
+    warnings: formattedWarnings,
   };
   if (result.errors.some(isLikelyASyntaxError)) {
     // If there are any syntax errors, show just them.
diff --git a/packages/react-dev-utils/getProcessForPort.js b/packages/react-dev-utils/getProcessForPort.js
index 24b89823eb6..2d9e531c381 100644
--- a/packages/react-dev-utils/getProcessForPort.js
+++ b/packages/react-dev-utils/getProcessForPort.js
@@ -18,8 +18,8 @@ var execOptions = {
   stdio: [
     'pipe', // stdin (default)
     'pipe', // stdout (default)
-    'ignore' //stderr
-  ]
+    'ignore', //stderr
+  ],
 };
 
 function isProcessAReactApp(processCommand) {
@@ -27,7 +27,10 @@ function isProcessAReactApp(processCommand) {
 }
 
 function getProcessIdOnPort(port) {
-  return execSync('lsof -i:' + port + ' -P -t -sTCP:LISTEN', execOptions).trim();
+  return execSync(
+    'lsof -i:' + port + ' -P -t -sTCP:LISTEN',
+    execOptions
+  ).trim();
 }
 
 function getPackageNameInDirectory(directory) {
@@ -35,26 +38,30 @@ function getPackageNameInDirectory(directory) {
 
   try {
     return require(packagePath).name;
-  } catch(e) {
+  } catch (e) {
     return null;
   }
-
 }
 
 function getProcessCommand(processId, processDirectory) {
-  var command = execSync('ps -o command -p ' + processId + ' | sed -n 2p', execOptions);
+  var command = execSync(
+    'ps -o command -p ' + processId + ' | sed -n 2p',
+    execOptions
+  );
 
   if (isProcessAReactApp(command)) {
     const packageName = getPackageNameInDirectory(processDirectory);
-    return (packageName) ? packageName + '\n' : command;
+    return packageName ? packageName + '\n' : command;
   } else {
     return command;
   }
-
 }
 
 function getDirectoryOfProcessById(processId) {
-  return execSync('lsof -p '+ processId + ' | awk \'$4=="cwd" {print $9}\'', execOptions).trim();
+  return execSync(
+    'lsof -p ' + processId + ' | awk \'$4=="cwd" {print $9}\'',
+    execOptions
+  ).trim();
 }
 
 function getProcessForPort(port) {
@@ -63,10 +70,9 @@ function getProcessForPort(port) {
     var directory = getDirectoryOfProcessById(processId);
     var command = getProcessCommand(processId, directory);
     return chalk.cyan(command) + chalk.blue('  in ') + chalk.cyan(directory);
-  } catch(e) {
+  } catch (e) {
     return null;
   }
 }
 
 module.exports = getProcessForPort;
-
diff --git a/packages/react-dev-utils/openBrowser.js b/packages/react-dev-utils/openBrowser.js
index 912c1819bcd..8c97f723c4f 100644
--- a/packages/react-dev-utils/openBrowser.js
+++ b/packages/react-dev-utils/openBrowser.js
@@ -30,22 +30,18 @@ function openBrowser(url) {
   // requested a different browser, we can try opening
   // Chrome with AppleScript. This lets us reuse an
   // existing tab when possible instead of creating a new one.
-  const shouldTryOpenChromeWithAppleScript = (
-    process.platform === 'darwin' && (
-      typeof browser !== 'string' ||
-      browser === OSX_CHROME
-    )
-  );
+  const shouldTryOpenChromeWithAppleScript = process.platform === 'darwin' &&
+    (typeof browser !== 'string' || browser === OSX_CHROME);
 
   if (shouldTryOpenChromeWithAppleScript) {
     try {
       // Try our best to reuse existing tab
       // on OS X Google Chrome with AppleScript
       execSync('ps cax | grep "Google Chrome"');
-      execSync(
-        'osascript openChrome.applescript ' + url,
-        {cwd: __dirname, stdio: 'ignore'}
-      );
+      execSync('osascript openChrome.applescript ' + url, {
+        cwd: __dirname,
+        stdio: 'ignore',
+      });
       return true;
     } catch (err) {
       // Ignore errors.
@@ -59,11 +55,11 @@ function openBrowser(url) {
   if (process.platform === 'darwin' && browser === 'open') {
     browser = undefined;
   }
-  
+
   // Fallback to opn
   // (It will always open new tab)
   try {
-    var options = {app: browser};
+    var options = { app: browser };
     opn(url, options).catch(() => {}); // Prevent `unhandledRejection` error.
     return true;
   } catch (err) {
diff --git a/packages/react-dev-utils/prompt.js b/packages/react-dev-utils/prompt.js
index e6e19cf39eb..4257924576d 100644
--- a/packages/react-dev-utils/prompt.js
+++ b/packages/react-dev-utils/prompt.js
@@ -16,7 +16,9 @@ var rl = require('readline');
 // You can control the behavior on <Enter> with `isYesDefault`.
 function prompt(question, isYesDefault) {
   if (typeof isYesDefault !== 'boolean') {
-    throw new Error('Provide explicit boolean isYesDefault as second argument.');
+    throw new Error(
+      'Provide explicit boolean isYesDefault as second argument.'
+    );
   }
   return new Promise(resolve => {
     var rlInterface = rl.createInterface({
diff --git a/packages/react-dev-utils/webpackHotDevClient.js b/packages/react-dev-utils/webpackHotDevClient.js
index b060ddea48c..77cc62be2b7 100644
--- a/packages/react-dev-utils/webpackHotDevClient.js
+++ b/packages/react-dev-utils/webpackHotDevClient.js
@@ -46,7 +46,7 @@ function createOverlayIframe(onIframeLoad) {
 }
 
 function addOverlayDivTo(iframe) {
-  var div =  iframe.contentDocument.createElement('div');
+  var div = iframe.contentDocument.createElement('div');
   div.id = 'react-dev-utils-webpack-hot-dev-client-overlay-div';
   div.style.position = 'fixed';
   div.style.boxSizing = 'border-box';
@@ -104,8 +104,9 @@ function ensureOverlayDivExists(onOverlayDivReady) {
 function showErrorOverlay(message) {
   ensureOverlayDivExists(function onOverlayDivReady(overlayDiv) {
     // Make it look similar to our terminal.
-    overlayDiv.innerHTML =
-      '<span style="color: ' + red + '">Failed to compile.</span><br><br>' +
+    overlayDiv.innerHTML = '<span style="color: ' +
+      red +
+      '">Failed to compile.</span><br><br>' +
       ansiHTML(entities.encode(message));
   });
 }
@@ -124,13 +125,15 @@ function destroyErrorOverlay() {
 }
 
 // Connect to WebpackDevServer via a socket.
-var connection = new SockJS(url.format({
-  protocol: window.location.protocol,
-  hostname: window.location.hostname,
-  port: window.location.port,
-  // Hardcoded in WebpackDevServer
-  pathname: '/sockjs-node'
-}));
+var connection = new SockJS(
+  url.format({
+    protocol: window.location.protocol,
+    hostname: window.location.hostname,
+    port: window.location.port,
+    // Hardcoded in WebpackDevServer
+    pathname: '/sockjs-node',
+  })
+);
 
 // Unlike WebpackDevServer client, we won't try to reconnect
 // to avoid spamming the console. Disconnect usually happens
@@ -207,7 +210,7 @@ function handleErrors(errors) {
   // "Massage" webpack messages.
   var formatted = formatWebpackMessages({
     errors: errors,
-    warnings: []
+    warnings: [],
   });
 
   // Only show the first error.
@@ -232,27 +235,27 @@ function handleAvailableHash(hash) {
 connection.onmessage = function(e) {
   var message = JSON.parse(e.data);
   switch (message.type) {
-  case 'hash':
-    handleAvailableHash(message.data);
-    break;
-  case 'still-ok':
-  case 'ok':
-    handleSuccess();
-    break;
-  case 'content-changed':
-    // Triggered when a file from `contentBase` changed.
-    window.location.reload();
-    break;
-  case 'warnings':
-    handleWarnings(message.data);
-    break;
-  case 'errors':
-    handleErrors(message.data);
-    break;
-  default:
+    case 'hash':
+      handleAvailableHash(message.data);
+      break;
+    case 'still-ok':
+    case 'ok':
+      handleSuccess();
+      break;
+    case 'content-changed':
+      // Triggered when a file from `contentBase` changed.
+      window.location.reload();
+      break;
+    case 'warnings':
+      handleWarnings(message.data);
+      break;
+    case 'errors':
+      handleErrors(message.data);
+      break;
+    default:
     // Do nothing.
   }
-}
+};
 
 // Is there a newer version of this code available?
 function isUpdateAvailable() {
@@ -297,7 +300,7 @@ function tryApplyUpdates(onHotUpdateSuccess) {
   }
 
   // https://webpack.github.io/docs/hot-module-replacement.html#check
-  var result = module.hot.check(/* autoApply */true, handleApplyUpdates);
+  var result = module.hot.check(/* autoApply */ true, handleApplyUpdates);
 
   // // Webpack 2 returns a Promise instead of invoking a callback
   if (result && result.then) {
diff --git a/packages/react-scripts/bin/react-scripts.js b/packages/react-scripts/bin/react-scripts.js
index 94a799fd89d..8a1175c99ea 100755
--- a/packages/react-scripts/bin/react-scripts.js
+++ b/packages/react-scripts/bin/react-scripts.js
@@ -15,36 +15,38 @@ var script = process.argv[2];
 var args = process.argv.slice(3);
 
 switch (script) {
-case 'build':
-case 'eject':
-case 'start':
-case 'test':
-  var result = spawn.sync(
-    'node',
-    [require.resolve('../scripts/' + script)].concat(args),
-    {stdio: 'inherit'}
-  );
-  if (result.signal) {
-    if (result.signal === 'SIGKILL') {
-      console.log(
-        'The build failed because the process exited too early. ' +
-        'This probably means the system ran out of memory or someone called ' +
-        '`kill -9` on the process.'
-      );
-    } else if (result.signal === 'SIGTERM') {
-      console.log(
-        'The build failed because the process exited too early. ' +
-        'Someone might have called `kill` or `killall`, or the system could ' +
-        'be shutting down.'
-      );
+  case 'build':
+  case 'eject':
+  case 'start':
+  case 'test':
+    var result = spawn.sync(
+      'node',
+      [require.resolve('../scripts/' + script)].concat(args),
+      { stdio: 'inherit' }
+    );
+    if (result.signal) {
+      if (result.signal === 'SIGKILL') {
+        console.log(
+          'The build failed because the process exited too early. ' +
+            'This probably means the system ran out of memory or someone called ' +
+            '`kill -9` on the process.'
+        );
+      } else if (result.signal === 'SIGTERM') {
+        console.log(
+          'The build failed because the process exited too early. ' +
+            'Someone might have called `kill` or `killall`, or the system could ' +
+            'be shutting down.'
+        );
+      }
+      process.exit(1);
     }
-    process.exit(1);
-  }
-  process.exit(result.status);
-  break;
-default:
-  console.log('Unknown script "' + script + '".');
-  console.log('Perhaps you need to update react-scripts?');
-  console.log('See: https://github.com/facebookincubator/create-react-app/blob/master/packages/react-scripts/template/README.md#updating-to-new-releases');
-  break;
+    process.exit(result.status);
+    break;
+  default:
+    console.log('Unknown script "' + script + '".');
+    console.log('Perhaps you need to update react-scripts?');
+    console.log(
+      'See: https://github.com/facebookincubator/create-react-app/blob/master/packages/react-scripts/template/README.md#updating-to-new-releases'
+    );
+    break;
 }
diff --git a/packages/react-scripts/config/env.js b/packages/react-scripts/config/env.js
index 50ac6556476..c018467a95b 100644
--- a/packages/react-scripts/config/env.js
+++ b/packages/react-scripts/config/env.js
@@ -15,30 +15,33 @@
 const REACT_APP = /^REACT_APP_/i;
 
 function getClientEnvironment(publicUrl) {
-  const raw = Object
-    .keys(process.env)
+  const raw = Object.keys(process.env)
     .filter(key => REACT_APP.test(key))
-    .reduce((env, key) => {
-      env[key] = process.env[key];
-      return env;
-    }, {
-      // Useful for determining whether we’re running in production mode.
-      // Most importantly, it switches React into the correct mode.
-      'NODE_ENV': process.env.NODE_ENV || 'development',
-      // Useful for resolving the correct path to static assets in `public`.
-      // For example, <img src={process.env.PUBLIC_URL + '/img/logo.png'} />.
-      // This should only be used as an escape hatch. Normally you would put
-      // images into the `src` and `import` them in code to get their paths.
-      'PUBLIC_URL': publicUrl
-    });
+    .reduce(
+      (env, key) => {
+        env[key] = process.env[key];
+        return env;
+      },
+      {
+        // Useful for determining whether we’re running in production mode.
+        // Most importantly, it switches React into the correct mode.
+        NODE_ENV: process.env.NODE_ENV || 'development',
+        // Useful for resolving the correct path to static assets in `public`.
+        // For example, <img src={process.env.PUBLIC_URL + '/img/logo.png'} />.
+        // This should only be used as an escape hatch. Normally you would put
+        // images into the `src` and `import` them in code to get their paths.
+        PUBLIC_URL: publicUrl,
+      }
+    );
   // Stringify all values so we can feed into Webpack DefinePlugin
   const stringified = {
-    'process.env': Object
-      .keys(raw)
-      .reduce((env, key) => {
+    'process.env': Object.keys(raw).reduce(
+      (env, key) => {
         env[key] = JSON.stringify(raw[key]);
         return env;
-      }, {})
+      },
+      {}
+    ),
   };
 
   return { raw, stringified };
diff --git a/packages/react-scripts/config/jest/babelTransform.js b/packages/react-scripts/config/jest/babelTransform.js
index ab212e99ecc..bee55b1b156 100644
--- a/packages/react-scripts/config/jest/babelTransform.js
+++ b/packages/react-scripts/config/jest/babelTransform.js
@@ -12,5 +12,5 @@ const babelJest = require('babel-jest');
 
 module.exports = babelJest.createTransformer({
   presets: [require.resolve('babel-preset-react-app')],
-  babelrc: false
+  babelrc: false,
 });
diff --git a/packages/react-scripts/config/paths.js b/packages/react-scripts/config/paths.js
index 0eba073ae96..76397756040 100644
--- a/packages/react-scripts/config/paths.js
+++ b/packages/react-scripts/config/paths.js
@@ -67,9 +67,8 @@ function getPublicUrl(appPackageJson) {
 // like /todos/42/static/js/bundle.7289d.js. We have to know the root.
 function getServedPath(appPackageJson) {
   const publicUrl = getPublicUrl(appPackageJson);
-  const servedUrl = envPublicUrl || (
-    publicUrl ? url.parse(publicUrl).pathname : '/'
-  );
+  const servedUrl = envPublicUrl ||
+    (publicUrl ? url.parse(publicUrl).pathname : '/');
   return ensureSlash(servedUrl, true);
 }
 
@@ -86,7 +85,7 @@ module.exports = {
   appNodeModules: resolveApp('node_modules'),
   nodePaths: nodePaths,
   publicUrl: getPublicUrl(resolveApp('package.json')),
-  servedPath: getServedPath(resolveApp('package.json'))
+  servedPath: getServedPath(resolveApp('package.json')),
 };
 
 // @remove-on-eject-begin
@@ -116,10 +115,14 @@ module.exports = {
 
 const ownPackageJson = require('../package.json');
 const reactScriptsPath = resolveApp(`node_modules/${ownPackageJson.name}`);
-const reactScriptsLinked = fs.existsSync(reactScriptsPath) && fs.lstatSync(reactScriptsPath).isSymbolicLink();
+const reactScriptsLinked = fs.existsSync(reactScriptsPath) &&
+  fs.lstatSync(reactScriptsPath).isSymbolicLink();
 
 // config before publish: we're in ./packages/react-scripts/config/
-if (!reactScriptsLinked && __dirname.indexOf(path.join('packages', 'react-scripts', 'config')) !== -1) {
+if (
+  !reactScriptsLinked &&
+  __dirname.indexOf(path.join('packages', 'react-scripts', 'config')) !== -1
+) {
   module.exports = {
     appPath: resolveApp('.'),
     appBuild: resolveOwn('../../build'),
diff --git a/packages/react-scripts/config/webpack.config.dev.js b/packages/react-scripts/config/webpack.config.dev.js
index 0fe461599d7..c7948b66f6e 100644
--- a/packages/react-scripts/config/webpack.config.dev.js
+++ b/packages/react-scripts/config/webpack.config.dev.js
@@ -61,7 +61,7 @@ module.exports = {
     // Errors should be considered fatal in development
     require.resolve('react-dev-utils/crashOverlay'),
     // Finally, this is your app's code:
-    paths.appIndexJs
+    paths.appIndexJs,
     // We include the app code last so that if there is a runtime error during
     // initialization, it doesn't blow up the WebpackDevServer client, and
     // changing JS code would still trigger a refresh.
@@ -76,7 +76,7 @@ module.exports = {
     // containing code from all our entry points, and the Webpack runtime.
     filename: 'static/js/bundle.js',
     // This is the URL that app is served from. We use "/" in development.
-    publicPath: publicPath
+    publicPath: publicPath,
   },
   resolve: {
     // This allows you to set a fallback for where Webpack should look for modules.
@@ -93,8 +93,8 @@ module.exports = {
     alias: {
       // Support React Native Web
       // https://www.smashingmagazine.com/2016/08/a-glimpse-into-the-future-with-react-native-for-web/
-      'react-native': 'react-native-web'
-    }
+      'react-native': 'react-native-web',
+    },
   },
   // @remove-on-eject-begin
   // Resolve loaders (webpack plugins for CSS, images, transpilation) from the
@@ -103,8 +103,8 @@ module.exports = {
     modules: [
       paths.ownNodeModules,
       // Lerna hoists everything, so we need to look in our app directory
-      paths.appNodeModules
-    ]
+      paths.appNodeModules,
+    ],
   },
   // @remove-on-eject-end
   module: {
@@ -116,17 +116,19 @@ module.exports = {
       {
         test: /\.(js|jsx)$/,
         enforce: 'pre',
-        use: [{
-          // @remove-on-eject-begin
-          // Point ESLint to our predefined config.
-          options: {
-            configFile: path.join(__dirname, '../eslintrc'),
-            useEslintrc: false
+        use: [
+          {
+            // @remove-on-eject-begin
+            // Point ESLint to our predefined config.
+            options: {
+              configFile: path.join(__dirname, '../eslintrc'),
+              useEslintrc: false,
+            },
+            // @remove-on-eject-end
+            loader: 'eslint-loader',
           },
-          // @remove-on-eject-end
-          loader: 'eslint-loader'
-        }],
-        include: paths.appSrc
+        ],
+        include: paths.appSrc,
       },
       // ** ADDING/UPDATING LOADERS **
       // The "url" loader handles all assets unless explicitly excluded.
@@ -146,28 +148,23 @@ module.exports = {
           /\.bmp$/,
           /\.gif$/,
           /\.jpe?g$/,
-          /\.png$/
+          /\.png$/,
         ],
         loader: 'file-loader',
         options: {
-          name: 'static/media/[name].[hash:8].[ext]'
-        }
+          name: 'static/media/[name].[hash:8].[ext]',
+        },
       },
       // "url" loader works like "file" loader except that it embeds assets
       // smaller than specified limit in bytes as data URLs to avoid requests.
       // A missing `test` is equivalent to a match.
       {
-        test: [
-          /\.bmp$/,
-          /\.gif$/,
-          /\.jpe?g$/,
-          /\.png$/
-        ],
+        test: [/\.bmp$/, /\.gif$/, /\.jpe?g$/, /\.png$/],
         loader: 'url-loader',
         options: {
           limit: 10000,
-          name: 'static/media/[name].[hash:8].[ext]'
-        }
+          name: 'static/media/[name].[hash:8].[ext]',
+        },
       },
       // Process JS with Babel.
       {
@@ -182,8 +179,8 @@ module.exports = {
           // This is a feature of `babel-loader` for webpack (not Babel itself).
           // It enables caching results in ./node_modules/.cache/babel-loader/
           // directory for faster rebuilds.
-          cacheDirectory: true
-        }
+          cacheDirectory: true,
+        },
       },
       // "postcss" loader applies autoprefixer to our CSS.
       // "css" loader resolves paths in CSS and adds assets as dependencies.
@@ -193,32 +190,34 @@ module.exports = {
       {
         test: /\.css$/,
         use: [
-          'style-loader', {
+          'style-loader',
+          {
             loader: 'css-loader',
             options: {
-              importLoaders: 1
-            }
-          }, {
+              importLoaders: 1,
+            },
+          },
+          {
             loader: 'postcss-loader',
             options: {
               ident: 'postcss', // https://webpack.js.org/guides/migrating/#complex-options
-              plugins:  () => ([
+              plugins: () => [
                 autoprefixer({
                   browsers: [
                     '>1%',
                     'last 4 versions',
                     'Firefox ESR',
                     'not ie < 9', // React doesn't support IE8 anyway
-                  ]
-                })
-              ])
-            }
-          }
-        ]
-      }
+                  ],
+                }),
+              ],
+            },
+          },
+        ],
+      },
       // ** STOP ** Are you adding a new loader?
       // Remember to add the new extension(s) to the "url" loader exclusion list.
-    ]
+    ],
   },
   plugins: [
     // Makes some environment variables available in index.html.
@@ -244,19 +243,19 @@ module.exports = {
     // to restart the development server for Webpack to discover it. This plugin
     // makes the discovery automatic so you don't have to restart.
     // See https://github.com/facebookincubator/create-react-app/issues/186
-    new WatchMissingNodeModulesPlugin(paths.appNodeModules)
+    new WatchMissingNodeModulesPlugin(paths.appNodeModules),
   ],
   // Some libraries import Node modules but don't use them in the browser.
   // Tell Webpack to provide empty mocks for them so importing them works.
   node: {
     fs: 'empty',
     net: 'empty',
-    tls: 'empty'
+    tls: 'empty',
   },
   // Turn off performance hints during development because we don't do any
   // splitting or minification in interest of speed. These warnings become
   // cumbersome.
   performance: {
-    hints: false
-  }
+    hints: false,
+  },
 };
diff --git a/packages/react-scripts/config/webpack.config.prod.js b/packages/react-scripts/config/webpack.config.prod.js
index dfa2b4a0ed6..979ed4e4d6d 100644
--- a/packages/react-scripts/config/webpack.config.prod.js
+++ b/packages/react-scripts/config/webpack.config.prod.js
@@ -51,8 +51,8 @@ const cssFilename = 'static/css/[name].[contenthash:8].css';
 // However, our output is structured with css, js and media folders.
 // To have this structure working with relative paths, we have to use custom options.
 const extractTextPluginOptions = shouldUseRelativeAssetPaths
-  // Making sure that the publicPath goes back to to build folder.
-  ? {publicPath: Array(cssFilename.split('/').length).join('../')}
+  ? // Making sure that the publicPath goes back to to build folder.
+    { publicPath: Array(cssFilename.split('/').length).join('../') }
   : {};
 
 // This is the production configuration.
@@ -65,10 +65,7 @@ module.exports = {
   // You can exclude the *.map files from the build during deployment.
   devtool: 'source-map',
   // In production, we only want to load the polyfills and the app code.
-  entry: [
-    require.resolve('./polyfills'),
-    paths.appIndexJs
-  ],
+  entry: [require.resolve('./polyfills'), paths.appIndexJs],
   output: {
     // The build folder.
     path: paths.appBuild,
@@ -78,7 +75,7 @@ module.exports = {
     filename: 'static/js/[name].[chunkhash:8].js',
     chunkFilename: 'static/js/[name].[chunkhash:8].chunk.js',
     // We inferred the "public path" (such as / or /my-project) from homepage.
-    publicPath: publicPath
+    publicPath: publicPath,
   },
   resolve: {
     // This allows you to set a fallback for where Webpack should look for modules.
@@ -95,8 +92,8 @@ module.exports = {
     alias: {
       // Support React Native Web
       // https://www.smashingmagazine.com/2016/08/a-glimpse-into-the-future-with-react-native-for-web/
-      'react-native': 'react-native-web'
-    }
+      'react-native': 'react-native-web',
+    },
   },
   // @remove-on-eject-begin
   // Resolve loaders (webpack plugins for CSS, images, transpilation) from the
@@ -105,8 +102,8 @@ module.exports = {
     modules: [
       paths.ownNodeModules,
       // Lerna hoists everything, so we need to look in our app directory
-      paths.appNodeModules
-    ]
+      paths.appNodeModules,
+    ],
   },
   // @remove-on-eject-end
   module: {
@@ -118,19 +115,21 @@ module.exports = {
       {
         test: /\.(js|jsx)$/,
         enforce: 'pre',
-        use: [{
-          // @remove-on-eject-begin
-          // Point ESLint to our predefined config.
-          options: {
-            // TODO: consider separate config for production,
-            // e.g. to enable no-console and no-debugger only in production.
-            configFile: path.join(__dirname, '../eslintrc'),
-            useEslintrc: false
+        use: [
+          {
+            // @remove-on-eject-begin
+            // Point ESLint to our predefined config.
+            options: {
+              // TODO: consider separate config for production,
+              // e.g. to enable no-console and no-debugger only in production.
+              configFile: path.join(__dirname, '../eslintrc'),
+              useEslintrc: false,
+            },
+            // @remove-on-eject-end
+            loader: 'eslint-loader',
           },
-          // @remove-on-eject-end
-          loader: 'eslint-loader'
-        }],
-        include: paths.appSrc
+        ],
+        include: paths.appSrc,
       },
       // ** ADDING/UPDATING LOADERS **
       // The "url" loader handles all assets unless explicitly excluded.
@@ -149,27 +148,22 @@ module.exports = {
           /\.bmp$/,
           /\.gif$/,
           /\.jpe?g$/,
-          /\.png$/
+          /\.png$/,
         ],
         loader: 'file-loader',
         options: {
-          name: 'static/media/[name].[hash:8].[ext]'
-        }
+          name: 'static/media/[name].[hash:8].[ext]',
+        },
       },
       // "url" loader works just like "file" loader but it also embeds
       // assets smaller than specified size as data URLs to avoid requests.
       {
-        test: [
-          /\.bmp$/,
-          /\.gif$/,
-          /\.jpe?g$/,
-          /\.png$/
-        ],
+        test: [/\.bmp$/, /\.gif$/, /\.jpe?g$/, /\.png$/],
         loader: 'url-loader',
         options: {
           limit: 10000,
-          name: 'static/media/[name].[hash:8].[ext]'
-        }
+          name: 'static/media/[name].[hash:8].[ext]',
+        },
       },
       // Process JS with Babel.
       {
@@ -197,37 +191,43 @@ module.exports = {
       // in the main CSS file.
       {
         test: /\.css$/,
-        loader: ExtractTextPlugin.extract(Object.assign({
-          fallback: 'style-loader',
-          use: [
+        loader: ExtractTextPlugin.extract(
+          Object.assign(
             {
-              loader: 'css-loader',
-              options: {
-                importLoaders: 1
-              }
-            }, {
-              loader: 'postcss-loader',
-              options: {
-                ident: 'postcss', // https://webpack.js.org/guides/migrating/#complex-options
-                plugins: () => ([
-                  autoprefixer({
-                    browsers: [
-                      '>1%',
-                      'last 4 versions',
-                      'Firefox ESR',
-                      'not ie < 9', // React doesn't support IE8 anyway
-                    ]
-                  })
-                ])
-              }
-            }
-          ]
-        }, extractTextPluginOptions))
+              fallback: 'style-loader',
+              use: [
+                {
+                  loader: 'css-loader',
+                  options: {
+                    importLoaders: 1,
+                  },
+                },
+                {
+                  loader: 'postcss-loader',
+                  options: {
+                    ident: 'postcss', // https://webpack.js.org/guides/migrating/#complex-options
+                    plugins: () => [
+                      autoprefixer({
+                        browsers: [
+                          '>1%',
+                          'last 4 versions',
+                          'Firefox ESR',
+                          'not ie < 9', // React doesn't support IE8 anyway
+                        ],
+                      }),
+                    ],
+                  },
+                },
+              ],
+            },
+            extractTextPluginOptions
+          )
+        ),
         // Note: this won't work without `new ExtractTextPlugin()` in `plugins`.
-      }
+      },
       // ** STOP ** Are you adding a new loader?
       // Remember to add the new extension(s) to the "url" loader exclusion list.
-    ]
+    ],
   },
   plugins: [
     // Makes some environment variables available in index.html.
@@ -250,8 +250,8 @@ module.exports = {
         keepClosingSlash: true,
         minifyJS: true,
         minifyCSS: true,
-        minifyURLs: true
-      }
+        minifyURLs: true,
+      },
     }),
     // Makes some environment variables available to the JS code, for example:
     // if (process.env.NODE_ENV === 'production') { ... }. See `./env.js`.
@@ -262,33 +262,33 @@ module.exports = {
     new webpack.optimize.UglifyJsPlugin({
       compress: {
         screw_ie8: true, // React doesn't support IE8
-        warnings: false
+        warnings: false,
       },
       mangle: {
-        screw_ie8: true
+        screw_ie8: true,
       },
       output: {
         comments: false,
-        screw_ie8: true
+        screw_ie8: true,
       },
-      sourceMap: true
+      sourceMap: true,
     }),
     // Note: this won't work without ExtractTextPlugin.extract(..) in `loaders`.
     new ExtractTextPlugin({
-      filename: cssFilename
+      filename: cssFilename,
     }),
     // Generate a manifest file which contains a mapping of all asset filenames
     // to their corresponding output file so that tools can pick it up without
     // having to parse `index.html`.
     new ManifestPlugin({
-      fileName: 'asset-manifest.json'
-    })
+      fileName: 'asset-manifest.json',
+    }),
   ],
   // Some libraries import Node modules but don't use them in the browser.
   // Tell Webpack to provide empty mocks for them so importing them works.
   node: {
     fs: 'empty',
     net: 'empty',
-    tls: 'empty'
-  }
+    tls: 'empty',
+  },
 };
diff --git a/packages/react-scripts/config/webpackDevServer.config.js b/packages/react-scripts/config/webpackDevServer.config.js
index 910f074fab5..37d9d1a750e 100644
--- a/packages/react-scripts/config/webpackDevServer.config.js
+++ b/packages/react-scripts/config/webpackDevServer.config.js
@@ -54,7 +54,7 @@ module.exports = {
   // Reportedly, this avoids CPU overload on some systems.
   // https://github.com/facebookincubator/create-react-app/issues/293
   watchOptions: {
-    ignored: /node_modules/
+    ignored: /node_modules/,
   },
   // Enable HTTPS if the HTTPS environment variable is set to 'true'
   https: protocol === 'https',
diff --git a/packages/react-scripts/fixtures/kitchensink/integration/env.test.js b/packages/react-scripts/fixtures/kitchensink/integration/env.test.js
index c3169c987a9..b90d12ab12e 100644
--- a/packages/react-scripts/fixtures/kitchensink/integration/env.test.js
+++ b/packages/react-scripts/fixtures/kitchensink/integration/env.test.js
@@ -7,36 +7,47 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  */
 
-import { expect } from 'chai'
-import initDOM from './initDOM'
+import { expect } from 'chai';
+import initDOM from './initDOM';
 
 describe('Integration', () => {
   describe('Environment variables', () => {
     it('file env variables', async () => {
-      const doc = await initDOM('file-env-variables')
+      const doc = await initDOM('file-env-variables');
 
-      expect(doc.getElementById('feature-file-env-variables').textContent).to.equal('fromtheenvfile.')
-    })
+      expect(
+        doc.getElementById('feature-file-env-variables').textContent
+      ).to.equal('fromtheenvfile.');
+    });
 
     it('NODE_PATH', async () => {
-      const doc = await initDOM('node-path')
+      const doc = await initDOM('node-path');
 
-      expect(doc.getElementById('feature-node-path').childElementCount).to.equal(4)
-    })
+      expect(
+        doc.getElementById('feature-node-path').childElementCount
+      ).to.equal(4);
+    });
 
     it('PUBLIC_URL', async () => {
-      const doc = await initDOM('public-url')
-
-      const prefix = process.env.NODE_ENV === 'development' ? '' : 'http://www.example.org/spa';
-      expect(doc.getElementById('feature-public-url').textContent).to.equal(`${prefix}.`)
-      expect(doc.querySelector('head link[rel="shortcut icon"]').getAttribute('href'))
-        .to.equal(`${prefix}/favicon.ico`)
-    })
+      const doc = await initDOM('public-url');
+
+      const prefix = process.env.NODE_ENV === 'development'
+        ? ''
+        : 'http://www.example.org/spa';
+      expect(doc.getElementById('feature-public-url').textContent).to.equal(
+        `${prefix}.`
+      );
+      expect(
+        doc.querySelector('head link[rel="shortcut icon"]').getAttribute('href')
+      ).to.equal(`${prefix}/favicon.ico`);
+    });
 
     it('shell env variables', async () => {
-      const doc = await initDOM('shell-env-variables')
-
-      expect(doc.getElementById('feature-shell-env-variables').textContent).to.equal('fromtheshell.')
-    })
-  })
-})
+      const doc = await initDOM('shell-env-variables');
+
+      expect(
+        doc.getElementById('feature-shell-env-variables').textContent
+      ).to.equal('fromtheshell.');
+    });
+  });
+});
diff --git a/packages/react-scripts/fixtures/kitchensink/integration/initDOM.js b/packages/react-scripts/fixtures/kitchensink/integration/initDOM.js
index 3cfb182148a..4d6f531ea84 100644
--- a/packages/react-scripts/fixtures/kitchensink/integration/initDOM.js
+++ b/packages/react-scripts/fixtures/kitchensink/integration/initDOM.js
@@ -7,59 +7,72 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  */
 
-const fs = require('fs')
-const http = require('http')
-const jsdom = require('jsdom')
-const path = require('path')
-const { expect } = require('chai')
+const fs = require('fs');
+const http = require('http');
+const jsdom = require('jsdom');
+const path = require('path');
+const { expect } = require('chai');
 
-let getMarkup
-let resourceLoader
+let getMarkup;
+let resourceLoader;
 
 if (process.env.E2E_FILE) {
   const file = path.isAbsolute(process.env.E2E_FILE)
     ? process.env.E2E_FILE
-    : path.join(process.cwd(), process.env.E2E_FILE)
+    : path.join(process.cwd(), process.env.E2E_FILE);
 
-  const markup = fs.readFileSync(file, 'utf8')
-  getMarkup = () => markup
+  const markup = fs.readFileSync(file, 'utf8');
+  getMarkup = () => markup;
 
-  const pathPrefix = process.env.PUBLIC_URL.replace(/^https?:\/\/[^/]+\/?/, '')
+  const pathPrefix = process.env.PUBLIC_URL.replace(/^https?:\/\/[^/]+\/?/, '');
 
-  resourceLoader = (resource, callback) => callback(
-    null,
-    fs.readFileSync(path.join(path.dirname(file), resource.url.pathname.replace(pathPrefix, '')), 'utf8')
-  )
+  resourceLoader = (resource, callback) =>
+    callback(
+      null,
+      fs.readFileSync(
+        path.join(
+          path.dirname(file),
+          resource.url.pathname.replace(pathPrefix, '')
+        ),
+        'utf8'
+      )
+    );
 } else if (process.env.E2E_URL) {
   getMarkup = () => new Promise(resolve => {
-    http.get(process.env.E2E_URL, (res) => {
-      let rawData = ''
-      res.on('data', chunk => rawData += chunk)
-      res.on('end', () => resolve(rawData))
-    })
-  })
+    http.get(process.env.E2E_URL, res => {
+      let rawData = '';
+      res.on('data', chunk => rawData += chunk);
+      res.on('end', () => resolve(rawData));
+    });
+  });
 
-  resourceLoader = (resource, callback) => resource.defaultFetch(callback)
+  resourceLoader = (resource, callback) => resource.defaultFetch(callback);
 } else {
-  it.only('can run jsdom (at least one of "E2E_FILE" or "E2E_URL" environment variables must be provided)', () => {
-    expect(new Error('This isn\'t the error you are looking for.')).to.be.undefined()
-  })
+  it.only(
+    'can run jsdom (at least one of "E2E_FILE" or "E2E_URL" environment variables must be provided)',
+    () => {
+      expect(
+        new Error("This isn't the error you are looking for.")
+      ).to.be.undefined();
+    }
+  );
 }
 
 export default feature => new Promise(async resolve => {
-  const markup = await getMarkup()
-  const host = process.env.E2E_URL || 'http://www.example.org/spa:3000'
+  const markup = await getMarkup();
+  const host = process.env.E2E_URL || 'http://www.example.org/spa:3000';
   const doc = jsdom.jsdom(markup, {
     features: {
       FetchExternalResources: ['script', 'css'],
       ProcessExternalResources: ['script'],
     },
-    created: (_, win) => win.addEventListener('ReactFeatureDidMount', () => resolve(doc), true),
+    created: (_, win) =>
+      win.addEventListener('ReactFeatureDidMount', () => resolve(doc), true),
     deferClose: true,
     resourceLoader,
     url: `${host}#${feature}`,
     virtualConsole: jsdom.createVirtualConsole().sendTo(console),
-  })
+  });
 
-  doc.close()
-})
+  doc.close();
+});
diff --git a/packages/react-scripts/fixtures/kitchensink/integration/syntax.test.js b/packages/react-scripts/fixtures/kitchensink/integration/syntax.test.js
index 8fe1990f20a..fc2a717befe 100644
--- a/packages/react-scripts/fixtures/kitchensink/integration/syntax.test.js
+++ b/packages/react-scripts/fixtures/kitchensink/integration/syntax.test.js
@@ -7,99 +7,129 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  */
 
-import { expect } from 'chai'
-import initDOM from './initDOM'
+import { expect } from 'chai';
+import initDOM from './initDOM';
 
 describe('Integration', () => {
   describe('Language syntax', () => {
     it('array destructuring', async () => {
-      const doc = await initDOM('array-destructuring')
+      const doc = await initDOM('array-destructuring');
 
-      expect(doc.getElementById('feature-array-destructuring').childElementCount).to.equal(4)
-    })
+      expect(
+        doc.getElementById('feature-array-destructuring').childElementCount
+      ).to.equal(4);
+    });
 
     it('array spread', async () => {
-      const doc = await initDOM('array-spread')
+      const doc = await initDOM('array-spread');
 
-      expect(doc.getElementById('feature-array-spread').childElementCount).to.equal(4)
-    })
+      expect(
+        doc.getElementById('feature-array-spread').childElementCount
+      ).to.equal(4);
+    });
 
     it('async/await', async () => {
-      const doc = await initDOM('async-await')
+      const doc = await initDOM('async-await');
 
-      expect(doc.getElementById('feature-async-await').childElementCount).to.equal(4)
-    })
+      expect(
+        doc.getElementById('feature-async-await').childElementCount
+      ).to.equal(4);
+    });
 
     it('class properties', async () => {
-      const doc = await initDOM('class-properties')
+      const doc = await initDOM('class-properties');
 
-      expect(doc.getElementById('feature-class-properties').childElementCount).to.equal(4)
-    })
+      expect(
+        doc.getElementById('feature-class-properties').childElementCount
+      ).to.equal(4);
+    });
 
     it('computed properties', async () => {
-      const doc = await initDOM('computed-properties')
+      const doc = await initDOM('computed-properties');
 
-      expect(doc.getElementById('feature-computed-properties').childElementCount).to.equal(4)
-    })
+      expect(
+        doc.getElementById('feature-computed-properties').childElementCount
+      ).to.equal(4);
+    });
 
     it('custom interpolation', async () => {
-      const doc = await initDOM('custom-interpolation')
+      const doc = await initDOM('custom-interpolation');
 
-      expect(doc.getElementById('feature-custom-interpolation').childElementCount).to.equal(4)
-    })
+      expect(
+        doc.getElementById('feature-custom-interpolation').childElementCount
+      ).to.equal(4);
+    });
 
     it('default parameters', async () => {
-      const doc = await initDOM('default-parameters')
+      const doc = await initDOM('default-parameters');
 
-      expect(doc.getElementById('feature-default-parameters').childElementCount).to.equal(4)
-    })
+      expect(
+        doc.getElementById('feature-default-parameters').childElementCount
+      ).to.equal(4);
+    });
 
     it('destructuring and await', async () => {
-      const doc = await initDOM('destructuring-and-await')
+      const doc = await initDOM('destructuring-and-await');
 
-      expect(doc.getElementById('feature-destructuring-and-await').childElementCount).to.equal(4)
-    })
+      expect(
+        doc.getElementById('feature-destructuring-and-await').childElementCount
+      ).to.equal(4);
+    });
 
     it('generators', async () => {
-      const doc = await initDOM('generators')
+      const doc = await initDOM('generators');
 
-      expect(doc.getElementById('feature-generators').childElementCount).to.equal(4)
-    })
+      expect(
+        doc.getElementById('feature-generators').childElementCount
+      ).to.equal(4);
+    });
 
     it('object destructuring', async () => {
-      const doc = await initDOM('object-destructuring')
+      const doc = await initDOM('object-destructuring');
 
-      expect(doc.getElementById('feature-object-destructuring').childElementCount).to.equal(4)
-    })
+      expect(
+        doc.getElementById('feature-object-destructuring').childElementCount
+      ).to.equal(4);
+    });
 
     it('object spread', async () => {
-      const doc = await initDOM('object-spread')
+      const doc = await initDOM('object-spread');
 
-      expect(doc.getElementById('feature-object-spread').childElementCount).to.equal(4)
-    })
+      expect(
+        doc.getElementById('feature-object-spread').childElementCount
+      ).to.equal(4);
+    });
 
     it('promises', async () => {
-      const doc = await initDOM('promises')
+      const doc = await initDOM('promises');
 
-      expect(doc.getElementById('feature-promises').childElementCount).to.equal(4)
-    })
+      expect(doc.getElementById('feature-promises').childElementCount).to.equal(
+        4
+      );
+    });
 
     it('rest + default', async () => {
-      const doc = await initDOM('rest-and-default')
+      const doc = await initDOM('rest-and-default');
 
-      expect(doc.getElementById('feature-rest-and-default').childElementCount).to.equal(4)
-    })
+      expect(
+        doc.getElementById('feature-rest-and-default').childElementCount
+      ).to.equal(4);
+    });
 
     it('rest parameters', async () => {
-      const doc = await initDOM('rest-parameters')
+      const doc = await initDOM('rest-parameters');
 
-      expect(doc.getElementById('feature-rest-parameters').childElementCount).to.equal(4)
-    })
+      expect(
+        doc.getElementById('feature-rest-parameters').childElementCount
+      ).to.equal(4);
+    });
 
     it('template interpolation', async () => {
-      const doc = await initDOM('template-interpolation')
-
-      expect(doc.getElementById('feature-template-interpolation').childElementCount).to.equal(4)
-    })
-  })
-})
+      const doc = await initDOM('template-interpolation');
+
+      expect(
+        doc.getElementById('feature-template-interpolation').childElementCount
+      ).to.equal(4);
+    });
+  });
+});
diff --git a/packages/react-scripts/fixtures/kitchensink/integration/webpack.test.js b/packages/react-scripts/fixtures/kitchensink/integration/webpack.test.js
index 43b3f1209f7..031786e0ee7 100644
--- a/packages/react-scripts/fixtures/kitchensink/integration/webpack.test.js
+++ b/packages/react-scripts/fixtures/kitchensink/integration/webpack.test.js
@@ -7,46 +7,57 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  */
 
-import { expect } from 'chai'
-import initDOM from './initDOM'
+import { expect } from 'chai';
+import initDOM from './initDOM';
 
 describe('Integration', () => {
   describe('Webpack plugins', () => {
     it('css inclusion', async () => {
-      const doc = await initDOM('css-inclusion')
+      const doc = await initDOM('css-inclusion');
 
-      expect(doc.getElementsByTagName('style')[0].textContent.replace(/\s/g, ''))
-        .to.match(/#feature-css-inclusion\{background:.+;color:.+}/)
-    })
+      expect(
+        doc.getElementsByTagName('style')[0].textContent.replace(/\s/g, '')
+      ).to.match(/#feature-css-inclusion\{background:.+;color:.+}/);
+    });
 
     it('image inclusion', async () => {
-      const doc = await initDOM('image-inclusion')
+      const doc = await initDOM('image-inclusion');
 
-      expect(doc.getElementById('feature-image-inclusion').src).to.match(/^data:image\/jpeg;base64.+==$/)
-    })
+      expect(doc.getElementById('feature-image-inclusion').src).to.match(
+        /^data:image\/jpeg;base64.+==$/
+      );
+    });
 
     it('no ext inclusion', async () => {
-      const doc = await initDOM('no-ext-inclusion')
+      const doc = await initDOM('no-ext-inclusion');
 
-      expect(doc.getElementById('feature-no-ext-inclusion').href).to.match(/\/static\/media\/aFileWithoutExt\.[a-f0-9]{8}\.bin$/)
-    })
+      expect(doc.getElementById('feature-no-ext-inclusion').href).to.match(
+        /\/static\/media\/aFileWithoutExt\.[a-f0-9]{8}\.bin$/
+      );
+    });
 
     it('json inclusion', async () => {
-      const doc = await initDOM('json-inclusion')
+      const doc = await initDOM('json-inclusion');
 
-      expect(doc.getElementById('feature-json-inclusion').textContent).to.equal('This is an abstract.')
-    })
+      expect(doc.getElementById('feature-json-inclusion').textContent).to.equal(
+        'This is an abstract.'
+      );
+    });
 
     it('svg inclusion', async () => {
-      const doc = await initDOM('svg-inclusion')
+      const doc = await initDOM('svg-inclusion');
 
-      expect(doc.getElementById('feature-svg-inclusion').src).to.match(/\/static\/media\/logo\..+\.svg$/)
-    })
+      expect(doc.getElementById('feature-svg-inclusion').src).to.match(
+        /\/static\/media\/logo\..+\.svg$/
+      );
+    });
 
     it('unknown ext inclusion', async () => {
-      const doc = await initDOM('unknown-ext-inclusion')
-
-      expect(doc.getElementById('feature-unknown-ext-inclusion').href).to.match(/\/static\/media\/aFileWithExt\.[a-f0-9]{8}\.unknown$/)
-    })
-  })
-})
+      const doc = await initDOM('unknown-ext-inclusion');
+
+      expect(doc.getElementById('feature-unknown-ext-inclusion').href).to.match(
+        /\/static\/media\/aFileWithExt\.[a-f0-9]{8}\.unknown$/
+      );
+    });
+  });
+});
diff --git a/packages/react-scripts/fixtures/kitchensink/src/App.js b/packages/react-scripts/fixtures/kitchensink/src/App.js
index ac55f7767e6..67de182b59e 100644
--- a/packages/react-scripts/fixtures/kitchensink/src/App.js
+++ b/packages/react-scripts/fixtures/kitchensink/src/App.js
@@ -11,8 +11,8 @@ import React, { Component, PropTypes, createElement } from 'react';
 
 class BuiltEmitter extends Component {
   static propTypes = {
-    feature: PropTypes.func.isRequired
-  }
+    feature: PropTypes.func.isRequired,
+  };
 
   componentDidMount() {
     const { feature } = this.props;
@@ -31,12 +31,12 @@ class BuiltEmitter extends Component {
   render() {
     const {
       props: { feature },
-      handleReady
+      handleReady,
     } = this;
     return (
       <div>
         {createElement(feature, {
-          onReady: handleReady
+          onReady: handleReady,
         })}
       </div>
     );
@@ -56,81 +56,113 @@ class App extends Component {
     const feature = location.hash.slice(1);
     switch (feature) {
       case 'array-destructuring':
-        import('./features/syntax/ArrayDestructuring').then(f => this.setFeature(f.default));
+        import(
+          './features/syntax/ArrayDestructuring'
+        ).then(f => this.setFeature(f.default));
         break;
       case 'array-spread':
-        import('./features/syntax/ArraySpread').then(f => this.setFeature(f.default));
+        import('./features/syntax/ArraySpread').then(f =>
+          this.setFeature(f.default));
         break;
       case 'async-await':
-        import('./features/syntax/AsyncAwait').then(f => this.setFeature(f.default));
+        import('./features/syntax/AsyncAwait').then(f =>
+          this.setFeature(f.default));
         break;
       case 'class-properties':
-        import('./features/syntax/ClassProperties').then(f => this.setFeature(f.default));
+        import('./features/syntax/ClassProperties').then(f =>
+          this.setFeature(f.default));
         break;
       case 'computed-properties':
-        import('./features/syntax/ComputedProperties').then(f => this.setFeature(f.default));
+        import(
+          './features/syntax/ComputedProperties'
+        ).then(f => this.setFeature(f.default));
         break;
       case 'css-inclusion':
-        import('./features/webpack/CssInclusion').then(f => this.setFeature(f.default));
+        import('./features/webpack/CssInclusion').then(f =>
+          this.setFeature(f.default));
         break;
       case 'custom-interpolation':
-        import('./features/syntax/CustomInterpolation').then(f => this.setFeature(f.default));
+        import(
+          './features/syntax/CustomInterpolation'
+        ).then(f => this.setFeature(f.default));
         break;
       case 'default-parameters':
-        import('./features/syntax/DefaultParameters').then(f => this.setFeature(f.default));
+        import('./features/syntax/DefaultParameters').then(f =>
+          this.setFeature(f.default));
         break;
       case 'destructuring-and-await':
-        import('./features/syntax/DestructuringAndAwait').then(f => this.setFeature(f.default));
+        import(
+          './features/syntax/DestructuringAndAwait'
+        ).then(f => this.setFeature(f.default));
         break;
       case 'file-env-variables':
-        import('./features/env/FileEnvVariables').then(f => this.setFeature(f.default));
+        import('./features/env/FileEnvVariables').then(f =>
+          this.setFeature(f.default));
         break;
       case 'generators':
-        import('./features/syntax/Generators').then(f => this.setFeature(f.default));
+        import('./features/syntax/Generators').then(f =>
+          this.setFeature(f.default));
         break;
       case 'image-inclusion':
-        import('./features/webpack/ImageInclusion').then(f => this.setFeature(f.default));
+        import('./features/webpack/ImageInclusion').then(f =>
+          this.setFeature(f.default));
         break;
       case 'json-inclusion':
-        import('./features/webpack/JsonInclusion').then(f => this.setFeature(f.default));
+        import('./features/webpack/JsonInclusion').then(f =>
+          this.setFeature(f.default));
         break;
       case 'node-path':
         import('./features/env/NodePath').then(f => this.setFeature(f.default));
         break;
       case 'no-ext-inclusion':
-        import('./features/webpack/NoExtInclusion').then(f => this.setFeature(f.default));
+        import('./features/webpack/NoExtInclusion').then(f =>
+          this.setFeature(f.default));
         break;
       case 'object-destructuring':
-        import('./features/syntax/ObjectDestructuring').then(f => this.setFeature(f.default));
+        import(
+          './features/syntax/ObjectDestructuring'
+        ).then(f => this.setFeature(f.default));
         break;
       case 'object-spread':
-        import('./features/syntax/ObjectSpread').then(f => this.setFeature(f.default));
+        import('./features/syntax/ObjectSpread').then(f =>
+          this.setFeature(f.default));
         break;
       case 'promises':
-        import('./features/syntax/Promises').then(f => this.setFeature(f.default));
+        import('./features/syntax/Promises').then(f =>
+          this.setFeature(f.default));
         break;
       case 'public-url':
-        import('./features/env/PublicUrl').then(f => this.setFeature(f.default));
+        import('./features/env/PublicUrl').then(f =>
+          this.setFeature(f.default));
         break;
       case 'rest-and-default':
-        import('./features/syntax/RestAndDefault').then(f => this.setFeature(f.default));
+        import('./features/syntax/RestAndDefault').then(f =>
+          this.setFeature(f.default));
         break;
       case 'rest-parameters':
-        import('./features/syntax/RestParameters').then(f => this.setFeature(f.default));
+        import('./features/syntax/RestParameters').then(f =>
+          this.setFeature(f.default));
         break;
       case 'shell-env-variables':
-        import('./features/env/ShellEnvVariables').then(f => this.setFeature(f.default));
+        import('./features/env/ShellEnvVariables').then(f =>
+          this.setFeature(f.default));
         break;
       case 'svg-inclusion':
-        import('./features/webpack/SvgInclusion').then(f => this.setFeature(f.default));
+        import('./features/webpack/SvgInclusion').then(f =>
+          this.setFeature(f.default));
         break;
       case 'template-interpolation':
-        import('./features/syntax/TemplateInterpolation').then(f => this.setFeature(f.default));
+        import(
+          './features/syntax/TemplateInterpolation'
+        ).then(f => this.setFeature(f.default));
         break;
       case 'unknown-ext-inclusion':
-        import('./features/webpack/UnknownExtInclusion').then(f => this.setFeature(f.default));
+        import(
+          './features/webpack/UnknownExtInclusion'
+        ).then(f => this.setFeature(f.default));
         break;
-      default: throw new Error(`Missing feature "${feature}"`);
+      default:
+        throw new Error(`Missing feature "${feature}"`);
     }
   }
 
diff --git a/packages/react-scripts/fixtures/kitchensink/src/absoluteLoad.js b/packages/react-scripts/fixtures/kitchensink/src/absoluteLoad.js
index a1fe21e48ff..0d01bc0a227 100644
--- a/packages/react-scripts/fixtures/kitchensink/src/absoluteLoad.js
+++ b/packages/react-scripts/fixtures/kitchensink/src/absoluteLoad.js
@@ -11,5 +11,5 @@ export default () => [
   { id: 1, name: '1' },
   { id: 2, name: '2' },
   { id: 3, name: '3' },
-  { id: 4, name: '4' }
-]
+  { id: 4, name: '4' },
+];
diff --git a/packages/react-scripts/fixtures/kitchensink/src/features/env/FileEnvVariables.js b/packages/react-scripts/fixtures/kitchensink/src/features/env/FileEnvVariables.js
index ff874b62812..a8a1e98fe71 100644
--- a/packages/react-scripts/fixtures/kitchensink/src/features/env/FileEnvVariables.js
+++ b/packages/react-scripts/fixtures/kitchensink/src/features/env/FileEnvVariables.js
@@ -7,8 +7,10 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  */
 
-import React from 'react'
+import React from 'react';
 
 export default () => (
-  <span id="feature-file-env-variables">{process.env.REACT_APP_FILE_ENV_MESSAGE}.</span>
-)
+  <span id="feature-file-env-variables">
+    {process.env.REACT_APP_FILE_ENV_MESSAGE}.
+  </span>
+);
diff --git a/packages/react-scripts/fixtures/kitchensink/src/features/env/NodePath.js b/packages/react-scripts/fixtures/kitchensink/src/features/env/NodePath.js
index e4b868e47b6..eb1a45c0f12 100644
--- a/packages/react-scripts/fixtures/kitchensink/src/features/env/NodePath.js
+++ b/packages/react-scripts/fixtures/kitchensink/src/features/env/NodePath.js
@@ -7,13 +7,13 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  */
 
-import React, { Component, PropTypes } from 'react'
-import load from 'absoluteLoad'
+import React, { Component, PropTypes } from 'react';
+import load from 'absoluteLoad';
 
 export default class extends Component {
   static propTypes = {
-    onReady: PropTypes.func.isRequired
-  }
+    onReady: PropTypes.func.isRequired,
+  };
 
   constructor(props) {
     super(props);
@@ -32,9 +32,7 @@ export default class extends Component {
   render() {
     return (
       <div id="feature-node-path">
-        {this.state.users.map(user => (
-          <div key={user.id}>{user.name}</div>
-        ))}
+        {this.state.users.map(user => <div key={user.id}>{user.name}</div>)}
       </div>
     );
   }
diff --git a/packages/react-scripts/fixtures/kitchensink/src/features/env/PublicUrl.js b/packages/react-scripts/fixtures/kitchensink/src/features/env/PublicUrl.js
index 4c61be73956..4ea9b96f8b2 100644
--- a/packages/react-scripts/fixtures/kitchensink/src/features/env/PublicUrl.js
+++ b/packages/react-scripts/fixtures/kitchensink/src/features/env/PublicUrl.js
@@ -7,8 +7,8 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  */
 
-import React from 'react'
+import React from 'react';
 
 export default () => (
   <span id="feature-public-url">{process.env.PUBLIC_URL}.</span>
-)
+);
diff --git a/packages/react-scripts/fixtures/kitchensink/src/features/env/ShellEnvVariables.js b/packages/react-scripts/fixtures/kitchensink/src/features/env/ShellEnvVariables.js
index 243bfc00935..8449097d69a 100644
--- a/packages/react-scripts/fixtures/kitchensink/src/features/env/ShellEnvVariables.js
+++ b/packages/react-scripts/fixtures/kitchensink/src/features/env/ShellEnvVariables.js
@@ -7,8 +7,10 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  */
 
-import React from 'react'
+import React from 'react';
 
 export default () => (
-  <span id="feature-shell-env-variables">{process.env.REACT_APP_SHELL_ENV_MESSAGE}.</span>
-)
+  <span id="feature-shell-env-variables">
+    {process.env.REACT_APP_SHELL_ENV_MESSAGE}.
+  </span>
+);
diff --git a/packages/react-scripts/fixtures/kitchensink/src/features/syntax/ArrayDestructuring.js b/packages/react-scripts/fixtures/kitchensink/src/features/syntax/ArrayDestructuring.js
index 48516d43fd3..3d18a5edeac 100644
--- a/packages/react-scripts/fixtures/kitchensink/src/features/syntax/ArrayDestructuring.js
+++ b/packages/react-scripts/fixtures/kitchensink/src/features/syntax/ArrayDestructuring.js
@@ -7,21 +7,16 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  */
 
-import React, { Component, PropTypes } from 'react'
+import React, { Component, PropTypes } from 'react';
 
 function load() {
-  return [
-    [1, '1'],
-    [2, '2'],
-    [3, '3'],
-    [4, '4']
-  ];
+  return [[1, '1'], [2, '2'], [3, '3'], [4, '4']];
 }
 
 export default class extends Component {
   static propTypes = {
-    onReady: PropTypes.func.isRequired
-  }
+    onReady: PropTypes.func.isRequired,
+  };
 
   constructor(props) {
     super(props);
@@ -42,7 +37,7 @@ export default class extends Component {
       <div id="feature-array-destructuring">
         {this.state.users.map(user => {
           const [id, name] = user;
-          return <div key={id}>{name}</div>
+          return <div key={id}>{name}</div>;
         })}
       </div>
     );
diff --git a/packages/react-scripts/fixtures/kitchensink/src/features/syntax/ArraySpread.js b/packages/react-scripts/fixtures/kitchensink/src/features/syntax/ArraySpread.js
index 9998589a138..4f9b174eb6f 100644
--- a/packages/react-scripts/fixtures/kitchensink/src/features/syntax/ArraySpread.js
+++ b/packages/react-scripts/fixtures/kitchensink/src/features/syntax/ArraySpread.js
@@ -7,21 +7,21 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  */
 
-import React, { Component, PropTypes } from 'react'
+import React, { Component, PropTypes } from 'react';
 
 function load(users) {
   return [
     { id: 1, name: '1' },
     { id: 2, name: '2' },
     { id: 3, name: '3' },
-    ...users
+    ...users,
   ];
 }
 
 export default class extends Component {
   static propTypes = {
-    onReady: PropTypes.func.isRequired
-  }
+    onReady: PropTypes.func.isRequired,
+  };
 
   constructor(props) {
     super(props);
@@ -40,9 +40,7 @@ export default class extends Component {
   render() {
     return (
       <div id="feature-array-spread">
-        {this.state.users.map(user => (
-          <div key={user.id}>{user.name}</div>
-        ))}
+        {this.state.users.map(user => <div key={user.id}>{user.name}</div>)}
       </div>
     );
   }
diff --git a/packages/react-scripts/fixtures/kitchensink/src/features/syntax/AsyncAwait.js b/packages/react-scripts/fixtures/kitchensink/src/features/syntax/AsyncAwait.js
index b5b6013f93c..6924d4f92d8 100644
--- a/packages/react-scripts/fixtures/kitchensink/src/features/syntax/AsyncAwait.js
+++ b/packages/react-scripts/fixtures/kitchensink/src/features/syntax/AsyncAwait.js
@@ -7,21 +7,21 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  */
 
-import React, { Component, PropTypes } from 'react'
+import React, { Component, PropTypes } from 'react';
 
 async function load() {
   return [
     { id: 1, name: '1' },
     { id: 2, name: '2' },
     { id: 3, name: '3' },
-    { id: 4, name: '4' }
+    { id: 4, name: '4' },
   ];
 }
 
 export default class extends Component {
   static propTypes = {
-    onReady: PropTypes.func.isRequired
-  }
+    onReady: PropTypes.func.isRequired,
+  };
 
   constructor(props) {
     super(props);
@@ -40,9 +40,7 @@ export default class extends Component {
   render() {
     return (
       <div id="feature-async-await">
-        {this.state.users.map(user => (
-          <div key={user.id}>{user.name}</div>
-        ))}
+        {this.state.users.map(user => <div key={user.id}>{user.name}</div>)}
       </div>
     );
   }
diff --git a/packages/react-scripts/fixtures/kitchensink/src/features/syntax/ClassProperties.js b/packages/react-scripts/fixtures/kitchensink/src/features/syntax/ClassProperties.js
index 63bd7ab0512..7be21952da5 100644
--- a/packages/react-scripts/fixtures/kitchensink/src/features/syntax/ClassProperties.js
+++ b/packages/react-scripts/fixtures/kitchensink/src/features/syntax/ClassProperties.js
@@ -7,30 +7,28 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  */
 
-import React, { Component, PropTypes } from 'react'
+import React, { Component, PropTypes } from 'react';
 
 export default class extends Component {
   static propTypes = {
-    onReady: PropTypes.func.isRequired
-  }
+    onReady: PropTypes.func.isRequired,
+  };
 
   users = [
     { id: 1, name: '1' },
     { id: 2, name: '2' },
     { id: 3, name: '3' },
-    { id: 4, name: '4' }
+    { id: 4, name: '4' },
   ];
 
   componentDidMount() {
-    this.props.onReady()
+    this.props.onReady();
   }
 
   render() {
     return (
       <div id="feature-class-properties">
-        {this.users.map(user => (
-          <div key={user.id}>{user.name}</div>
-        ))}
+        {this.users.map(user => <div key={user.id}>{user.name}</div>)}
       </div>
     );
   }
diff --git a/packages/react-scripts/fixtures/kitchensink/src/features/syntax/ComputedProperties.js b/packages/react-scripts/fixtures/kitchensink/src/features/syntax/ComputedProperties.js
index 6e8c2c1ff1d..fc64c2a86e3 100644
--- a/packages/react-scripts/fixtures/kitchensink/src/features/syntax/ComputedProperties.js
+++ b/packages/react-scripts/fixtures/kitchensink/src/features/syntax/ComputedProperties.js
@@ -7,21 +7,21 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  */
 
-import React, { Component, PropTypes } from 'react'
+import React, { Component, PropTypes } from 'react';
 
 function load(prefix) {
   return [
     { id: 1, [`${prefix} name`]: '1' },
     { id: 2, [`${prefix} name`]: '2' },
     { id: 3, [`${prefix} name`]: '3' },
-    { id: 4, [`${prefix} name`]: '4' }
+    { id: 4, [`${prefix} name`]: '4' },
   ];
 }
 
 export default class extends Component {
   static propTypes = {
-    onReady: PropTypes.func.isRequired
-  }
+    onReady: PropTypes.func.isRequired,
+  };
 
   constructor(props) {
     super(props);
diff --git a/packages/react-scripts/fixtures/kitchensink/src/features/syntax/CustomInterpolation.js b/packages/react-scripts/fixtures/kitchensink/src/features/syntax/CustomInterpolation.js
index 399280d0190..e97902545e1 100644
--- a/packages/react-scripts/fixtures/kitchensink/src/features/syntax/CustomInterpolation.js
+++ b/packages/react-scripts/fixtures/kitchensink/src/features/syntax/CustomInterpolation.js
@@ -7,26 +7,28 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  */
 
-import React, { Component, PropTypes } from 'react'
+import React, { Component, PropTypes } from 'react';
 
-const styled = ([style]) => style.trim()
-  .split(/\s*;\s*/)
-  .map(rule => rule.split(/\s*:\s*/))
-  .reduce((rules, rule) => ({ ...rules, [rule[0]]: rule[1] }), {});
+const styled = ([style]) =>
+  style
+    .trim()
+    .split(/\s*;\s*/)
+    .map(rule => rule.split(/\s*:\s*/))
+    .reduce((rules, rule) => ({ ...rules, [rule[0]]: rule[1] }), {});
 
 function load() {
   return [
     { id: 1, name: '1' },
     { id: 2, name: '2' },
     { id: 3, name: '3' },
-    { id: 4, name: '4' }
+    { id: 4, name: '4' },
   ];
 }
 
 export default class extends Component {
   static propTypes = {
-    onReady: PropTypes.func.isRequired
-  }
+    onReady: PropTypes.func.isRequired,
+  };
 
   constructor(props) {
     super(props);
diff --git a/packages/react-scripts/fixtures/kitchensink/src/features/syntax/DefaultParameters.js b/packages/react-scripts/fixtures/kitchensink/src/features/syntax/DefaultParameters.js
index fd4054e56cb..74bbe4d3c17 100644
--- a/packages/react-scripts/fixtures/kitchensink/src/features/syntax/DefaultParameters.js
+++ b/packages/react-scripts/fixtures/kitchensink/src/features/syntax/DefaultParameters.js
@@ -7,21 +7,21 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  */
 
-import React, { Component, PropTypes } from 'react'
+import React, { Component, PropTypes } from 'react';
 
 function load(id = 0) {
   return [
     { id: id + 1, name: '1' },
     { id: id + 2, name: '2' },
     { id: id + 3, name: '3' },
-    { id: id + 4, name: '4' }
+    { id: id + 4, name: '4' },
   ];
 }
 
 export default class extends Component {
   static propTypes = {
-    onReady: PropTypes.func.isRequired
-  }
+    onReady: PropTypes.func.isRequired,
+  };
 
   constructor(props) {
     super(props);
@@ -40,9 +40,7 @@ export default class extends Component {
   render() {
     return (
       <div id="feature-default-parameters">
-        {this.state.users.map(user => (
-          <div key={user.id}>{user.name}</div>
-        ))}
+        {this.state.users.map(user => <div key={user.id}>{user.name}</div>)}
       </div>
     );
   }
diff --git a/packages/react-scripts/fixtures/kitchensink/src/features/syntax/DestructuringAndAwait.js b/packages/react-scripts/fixtures/kitchensink/src/features/syntax/DestructuringAndAwait.js
index c2345f5ce54..ede416944fc 100644
--- a/packages/react-scripts/fixtures/kitchensink/src/features/syntax/DestructuringAndAwait.js
+++ b/packages/react-scripts/fixtures/kitchensink/src/features/syntax/DestructuringAndAwait.js
@@ -7,21 +7,23 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  */
 
-import React, { Component, PropTypes } from 'react'
+import React, { Component, PropTypes } from 'react';
 
 async function load() {
-  return { users: [
-    { id: 1, name: '1' },
-    { id: 2, name: '2' },
-    { id: 3, name: '3' },
-    { id: 4, name: '4' }
-  ] };
+  return {
+    users: [
+      { id: 1, name: '1' },
+      { id: 2, name: '2' },
+      { id: 3, name: '3' },
+      { id: 4, name: '4' },
+    ],
+  };
 }
 
 export default class extends Component {
   static propTypes = {
-    onReady: PropTypes.func.isRequired
-  }
+    onReady: PropTypes.func.isRequired,
+  };
 
   constructor(props) {
     super(props);
@@ -40,9 +42,7 @@ export default class extends Component {
   render() {
     return (
       <div id="feature-destructuring-and-await">
-        {this.state.users.map(user => (
-          <div key={user.id}>{user.name}</div>
-        ))}
+        {this.state.users.map(user => <div key={user.id}>{user.name}</div>)}
       </div>
     );
   }
diff --git a/packages/react-scripts/fixtures/kitchensink/src/features/syntax/Generators.js b/packages/react-scripts/fixtures/kitchensink/src/features/syntax/Generators.js
index 170f00a7f0d..77b7bffd252 100644
--- a/packages/react-scripts/fixtures/kitchensink/src/features/syntax/Generators.js
+++ b/packages/react-scripts/fixtures/kitchensink/src/features/syntax/Generators.js
@@ -7,9 +7,9 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  */
 
-import React, { Component, PropTypes } from 'react'
+import React, { Component, PropTypes } from 'react';
 
-function * load(limit) {
+function* load(limit) {
   let i = 1;
   while (i <= limit) {
     yield { id: i, name: i };
@@ -19,8 +19,8 @@ function * load(limit) {
 
 export default class extends Component {
   static propTypes = {
-    onReady: PropTypes.func.isRequired
-  }
+    onReady: PropTypes.func.isRequired,
+  };
 
   constructor(props) {
     super(props);
@@ -42,9 +42,7 @@ export default class extends Component {
   render() {
     return (
       <div id="feature-generators">
-        {this.state.users.map(user => (
-          <div key={user.id}>{user.name}</div>
-        ))}
+        {this.state.users.map(user => <div key={user.id}>{user.name}</div>)}
       </div>
     );
   }
diff --git a/packages/react-scripts/fixtures/kitchensink/src/features/syntax/ObjectDestructuring.js b/packages/react-scripts/fixtures/kitchensink/src/features/syntax/ObjectDestructuring.js
index 025920b7f31..14fa6969ee5 100644
--- a/packages/react-scripts/fixtures/kitchensink/src/features/syntax/ObjectDestructuring.js
+++ b/packages/react-scripts/fixtures/kitchensink/src/features/syntax/ObjectDestructuring.js
@@ -7,21 +7,21 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  */
 
-import React, { Component, PropTypes } from 'react'
+import React, { Component, PropTypes } from 'react';
 
 function load() {
   return [
     { id: 1, name: '1' },
     { id: 2, name: '2' },
     { id: 3, name: '3' },
-    { id: 4, name: '4' }
+    { id: 4, name: '4' },
   ];
 }
 
 export default class extends Component {
   static propTypes = {
-    onReady: PropTypes.func.isRequired
-  }
+    onReady: PropTypes.func.isRequired,
+  };
 
   constructor(props) {
     super(props);
@@ -42,7 +42,7 @@ export default class extends Component {
       <div id="feature-object-destructuring">
         {this.state.users.map(user => {
           const { id, name } = user;
-          return <div key={id}>{name}</div>
+          return <div key={id}>{name}</div>;
         })}
       </div>
     );
diff --git a/packages/react-scripts/fixtures/kitchensink/src/features/syntax/ObjectSpread.js b/packages/react-scripts/fixtures/kitchensink/src/features/syntax/ObjectSpread.js
index d5de0aef31a..bf3fb26b80c 100644
--- a/packages/react-scripts/fixtures/kitchensink/src/features/syntax/ObjectSpread.js
+++ b/packages/react-scripts/fixtures/kitchensink/src/features/syntax/ObjectSpread.js
@@ -7,21 +7,21 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  */
 
-import React, { Component, PropTypes } from 'react'
+import React, { Component, PropTypes } from 'react';
 
 function load(baseUser) {
   return [
     { id: 1, name: '1', ...baseUser },
     { id: 2, name: '2', ...baseUser },
     { id: 3, name: '3', ...baseUser },
-    { id: 4, name: '4', ...baseUser }
+    { id: 4, name: '4', ...baseUser },
   ];
 }
 
 export default class extends Component {
   static propTypes = {
-    onReady: PropTypes.func.isRequired
-  }
+    onReady: PropTypes.func.isRequired,
+  };
 
   constructor(props) {
     super(props);
diff --git a/packages/react-scripts/fixtures/kitchensink/src/features/syntax/Promises.js b/packages/react-scripts/fixtures/kitchensink/src/features/syntax/Promises.js
index 8b362fccf2c..26438012cf2 100644
--- a/packages/react-scripts/fixtures/kitchensink/src/features/syntax/Promises.js
+++ b/packages/react-scripts/fixtures/kitchensink/src/features/syntax/Promises.js
@@ -7,21 +7,21 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  */
 
-import React, { Component, PropTypes } from 'react'
+import React, { Component, PropTypes } from 'react';
 
 function load() {
   return Promise.resolve([
     { id: 1, name: '1' },
     { id: 2, name: '2' },
     { id: 3, name: '3' },
-    { id: 4, name: '4' }
+    { id: 4, name: '4' },
   ]);
 }
 
 export default class extends Component {
   static propTypes = {
-    onReady: PropTypes.func.isRequired
-  }
+    onReady: PropTypes.func.isRequired,
+  };
 
   constructor(props) {
     super(props);
@@ -41,9 +41,7 @@ export default class extends Component {
   render() {
     return (
       <div id="feature-promises">
-        {this.state.users.map(user => (
-          <div key={user.id}>{user.name}</div>
-        ))}
+        {this.state.users.map(user => <div key={user.id}>{user.name}</div>)}
       </div>
     );
   }
diff --git a/packages/react-scripts/fixtures/kitchensink/src/features/syntax/RestAndDefault.js b/packages/react-scripts/fixtures/kitchensink/src/features/syntax/RestAndDefault.js
index 47d011f2eae..411ce33d4b9 100644
--- a/packages/react-scripts/fixtures/kitchensink/src/features/syntax/RestAndDefault.js
+++ b/packages/react-scripts/fixtures/kitchensink/src/features/syntax/RestAndDefault.js
@@ -7,21 +7,21 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  */
 
-import React, { Component, PropTypes } from 'react'
+import React, { Component, PropTypes } from 'react';
 
 function load({ id, ...rest } = { id: 0, user: { id: 42, name: '42' } }) {
   return [
     { id: id + 1, name: '1' },
     { id: id + 2, name: '2' },
     { id: id + 3, name: '3' },
-    rest.user
+    rest.user,
   ];
 }
 
 export default class extends Component {
   static propTypes = {
-    onReady: PropTypes.func.isRequired
-  }
+    onReady: PropTypes.func.isRequired,
+  };
 
   constructor(props) {
     super(props);
@@ -40,9 +40,7 @@ export default class extends Component {
   render() {
     return (
       <div id="feature-rest-and-default">
-        {this.state.users.map(user => (
-          <div key={user.id}>{user.name}</div>
-        ))}
+        {this.state.users.map(user => <div key={user.id}>{user.name}</div>)}
       </div>
     );
   }
diff --git a/packages/react-scripts/fixtures/kitchensink/src/features/syntax/RestParameters.js b/packages/react-scripts/fixtures/kitchensink/src/features/syntax/RestParameters.js
index 1a6cf7c1687..aaca55c0f96 100644
--- a/packages/react-scripts/fixtures/kitchensink/src/features/syntax/RestParameters.js
+++ b/packages/react-scripts/fixtures/kitchensink/src/features/syntax/RestParameters.js
@@ -7,21 +7,21 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  */
 
-import React, { Component, PropTypes } from 'react'
+import React, { Component, PropTypes } from 'react';
 
 function load({ id = 0, ...rest }) {
   return [
     { id: id + 1, name: '1' },
     { id: id + 2, name: '2' },
     { id: id + 3, name: '3' },
-    rest.user
+    rest.user,
   ];
 }
 
 export default class extends Component {
   static propTypes = {
-    onReady: PropTypes.func.isRequired
-  }
+    onReady: PropTypes.func.isRequired,
+  };
 
   constructor(props) {
     super(props);
@@ -40,9 +40,7 @@ export default class extends Component {
   render() {
     return (
       <div id="feature-rest-parameters">
-        {this.state.users.map(user => (
-          <div key={user.id}>{user.name}</div>
-        ))}
+        {this.state.users.map(user => <div key={user.id}>{user.name}</div>)}
       </div>
     );
   }
diff --git a/packages/react-scripts/fixtures/kitchensink/src/features/syntax/TemplateInterpolation.js b/packages/react-scripts/fixtures/kitchensink/src/features/syntax/TemplateInterpolation.js
index ff46e1c72f8..738a0b103ef 100644
--- a/packages/react-scripts/fixtures/kitchensink/src/features/syntax/TemplateInterpolation.js
+++ b/packages/react-scripts/fixtures/kitchensink/src/features/syntax/TemplateInterpolation.js
@@ -7,21 +7,21 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  */
 
-import React, { Component, PropTypes } from 'react'
+import React, { Component, PropTypes } from 'react';
 
 function load(name) {
   return [
     { id: 1, name: `${name}1` },
     { id: 2, name: `${name}2` },
     { id: 3, name: `${name}3` },
-    { id: 4, name: `${name}4` }
+    { id: 4, name: `${name}4` },
   ];
 }
 
 export default class extends Component {
   static propTypes = {
-    onReady: PropTypes.func.isRequired
-  }
+    onReady: PropTypes.func.isRequired,
+  };
 
   constructor(props) {
     super(props);
@@ -40,9 +40,7 @@ export default class extends Component {
   render() {
     return (
       <div id="feature-template-interpolation">
-        {this.state.users.map(user => (
-          <div key={user.id}>{user.name}</div>
-        ))}
+        {this.state.users.map(user => <div key={user.id}>{user.name}</div>)}
       </div>
     );
   }
diff --git a/packages/react-scripts/fixtures/kitchensink/src/features/webpack/CssInclusion.js b/packages/react-scripts/fixtures/kitchensink/src/features/webpack/CssInclusion.js
index 7c46c7208b7..ab7c9a2d86e 100644
--- a/packages/react-scripts/fixtures/kitchensink/src/features/webpack/CssInclusion.js
+++ b/packages/react-scripts/fixtures/kitchensink/src/features/webpack/CssInclusion.js
@@ -7,9 +7,7 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  */
 
-import React from 'react'
-import './assets/style.css'
+import React from 'react';
+import './assets/style.css';
 
-export default () => (
-  <p id="feature-css-inclusion">We love useless text.</p>
-)
+export default () => <p id="feature-css-inclusion">We love useless text.</p>;
diff --git a/packages/react-scripts/fixtures/kitchensink/src/features/webpack/ImageInclusion.js b/packages/react-scripts/fixtures/kitchensink/src/features/webpack/ImageInclusion.js
index c4560ff9dae..a6ca7aaa818 100644
--- a/packages/react-scripts/fixtures/kitchensink/src/features/webpack/ImageInclusion.js
+++ b/packages/react-scripts/fixtures/kitchensink/src/features/webpack/ImageInclusion.js
@@ -7,9 +7,9 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  */
 
-import React from 'react'
-import tiniestCat from './assets/tiniest-cat.jpg'
+import React from 'react';
+import tiniestCat from './assets/tiniest-cat.jpg';
 
 export default () => (
   <img id="feature-image-inclusion" src={tiniestCat} alt="tiniest cat" />
-)
+);
diff --git a/packages/react-scripts/fixtures/kitchensink/src/features/webpack/JsonInclusion.js b/packages/react-scripts/fixtures/kitchensink/src/features/webpack/JsonInclusion.js
index 552a8be7b1a..e81f7639736 100644
--- a/packages/react-scripts/fixtures/kitchensink/src/features/webpack/JsonInclusion.js
+++ b/packages/react-scripts/fixtures/kitchensink/src/features/webpack/JsonInclusion.js
@@ -7,9 +7,7 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  */
 
-import React from 'react'
-import { abstract } from './assets/abstract.json'
+import React from 'react';
+import { abstract } from './assets/abstract.json';
 
-export default () => (
-  <summary id="feature-json-inclusion">{abstract}</summary>
-)
+export default () => <summary id="feature-json-inclusion">{abstract}</summary>;
diff --git a/packages/react-scripts/fixtures/kitchensink/src/features/webpack/NoExtInclusion.js b/packages/react-scripts/fixtures/kitchensink/src/features/webpack/NoExtInclusion.js
index b3bdbe9fcbc..7f824c2f292 100644
--- a/packages/react-scripts/fixtures/kitchensink/src/features/webpack/NoExtInclusion.js
+++ b/packages/react-scripts/fixtures/kitchensink/src/features/webpack/NoExtInclusion.js
@@ -7,13 +7,13 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  */
 
-import React from 'react'
-import aFileWithoutExt from './assets/aFileWithoutExt'
+import React from 'react';
+import aFileWithoutExt from './assets/aFileWithoutExt';
 
 const text = aFileWithoutExt.includes('base64')
   ? atob(aFileWithoutExt.split('base64,')[1]).trim()
-  : aFileWithoutExt
+  : aFileWithoutExt;
 
 export default () => (
   <a id="feature-no-ext-inclusion" href={text}>aFileWithoutExt</a>
-)
+);
diff --git a/packages/react-scripts/fixtures/kitchensink/src/features/webpack/SvgInclusion.js b/packages/react-scripts/fixtures/kitchensink/src/features/webpack/SvgInclusion.js
index f82e5f2911c..8876021aed6 100644
--- a/packages/react-scripts/fixtures/kitchensink/src/features/webpack/SvgInclusion.js
+++ b/packages/react-scripts/fixtures/kitchensink/src/features/webpack/SvgInclusion.js
@@ -7,9 +7,7 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  */
 
-import React from 'react'
-import logo from './assets/logo.svg'
+import React from 'react';
+import logo from './assets/logo.svg';
 
-export default () => (
-  <img id="feature-svg-inclusion" src={logo} alt="logo" />
-)
+export default () => <img id="feature-svg-inclusion" src={logo} alt="logo" />;
diff --git a/packages/react-scripts/fixtures/kitchensink/src/features/webpack/UnknownExtInclusion.js b/packages/react-scripts/fixtures/kitchensink/src/features/webpack/UnknownExtInclusion.js
index a9ac8f00cf1..70b046e9532 100644
--- a/packages/react-scripts/fixtures/kitchensink/src/features/webpack/UnknownExtInclusion.js
+++ b/packages/react-scripts/fixtures/kitchensink/src/features/webpack/UnknownExtInclusion.js
@@ -7,13 +7,13 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  */
 
-import React from 'react'
-import aFileWithExtUnknown from './assets/aFileWithExt.unknown'
+import React from 'react';
+import aFileWithExtUnknown from './assets/aFileWithExt.unknown';
 
 const text = aFileWithExtUnknown.includes('base64')
   ? atob(aFileWithExtUnknown.split('base64,')[1]).trim()
-  : aFileWithExtUnknown
+  : aFileWithExtUnknown;
 
 export default () => (
   <a id="feature-unknown-ext-inclusion" href={text}>aFileWithExtUnknown</a>
-)
+);
diff --git a/packages/react-scripts/fixtures/kitchensink/src/index.js b/packages/react-scripts/fixtures/kitchensink/src/index.js
index dc1143691f2..46fb0dd2e55 100644
--- a/packages/react-scripts/fixtures/kitchensink/src/index.js
+++ b/packages/react-scripts/fixtures/kitchensink/src/index.js
@@ -11,7 +11,4 @@ import React from 'react';
 import ReactDOM from 'react-dom';
 import App from './App';
 
-ReactDOM.render(
-  <App />,
-  document.getElementById('root')
-);
+ReactDOM.render(<App />, document.getElementById('root'));
diff --git a/packages/react-scripts/fixtures/kitchensink/src/subfolder/lol.js b/packages/react-scripts/fixtures/kitchensink/src/subfolder/lol.js
index c844f831d31..979cb3e7206 100644
--- a/packages/react-scripts/fixtures/kitchensink/src/subfolder/lol.js
+++ b/packages/react-scripts/fixtures/kitchensink/src/subfolder/lol.js
@@ -7,4 +7,6 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  */
 
-module.exports = function() { return `haha` }
+module.exports = function() {
+  return `haha`;
+};
diff --git a/packages/react-scripts/scripts/build.js b/packages/react-scripts/scripts/build.js
index b6c6ddf893d..548ff3cc68e 100644
--- a/packages/react-scripts/scripts/build.js
+++ b/packages/react-scripts/scripts/build.js
@@ -17,7 +17,7 @@ process.env.NODE_ENV = 'production';
 // if this file is missing. dotenv will never modify any environment variables
 // that have already been set.
 // https://github.com/motdotla/dotenv
-require('dotenv').config({silent: true});
+require('dotenv').config({ silent: true });
 
 const chalk = require('chalk');
 const fs = require('fs-extra');
@@ -86,9 +86,12 @@ function build(previousFileSizes) {
     }
 
     if (process.env.CI && stats.compilation.warnings.length) {
-     printErrors('Failed to compile. When process.env.CI = true, warnings are treated as failures. Most CI servers set this automatically.', stats.compilation.warnings);
-     process.exit(1);
-   }
+      printErrors(
+        'Failed to compile. When process.env.CI = true, warnings are treated as failures. Most CI servers set this automatically.',
+        stats.compilation.warnings
+      );
+      process.exit(1);
+    }
 
     console.log(chalk.green('Compiled successfully.'));
     console.log();
@@ -99,14 +102,18 @@ function build(previousFileSizes) {
     console.log();
 
     const openCommand = process.platform === 'win32' ? 'start' : 'open';
-    const appPackage  = require(paths.appPackageJson);
+    const appPackage = require(paths.appPackageJson);
     const publicUrl = paths.publicUrl;
     const publicPath = config.output.publicPath;
     const publicPathname = url.parse(publicPath).pathname;
     if (publicUrl && publicUrl.indexOf('.github.io/') !== -1) {
       // "homepage": "http://user.github.io/project"
-      console.log(`The project was built assuming it is hosted at ${chalk.green(publicPathname)}.`);
-      console.log(`You can control this with the ${chalk.green('homepage')} field in your ${chalk.cyan('package.json')}.`);
+      console.log(
+        `The project was built assuming it is hosted at ${chalk.green(publicPathname)}.`
+      );
+      console.log(
+        `You can control this with the ${chalk.green('homepage')} field in your ${chalk.cyan('package.json')}.`
+      );
       console.log();
       console.log(`The ${chalk.cyan('build')} folder is ready to be deployed.`);
       console.log(`To publish it at ${chalk.green(publicUrl)}, run:`);
@@ -119,13 +126,19 @@ function build(previousFileSizes) {
           console.log(`  ${chalk.cyan('npm')} install --save-dev gh-pages`);
         }
         console.log();
-        console.log(`Add the following script in your ${chalk.cyan('package.json')}.`);
+        console.log(
+          `Add the following script in your ${chalk.cyan('package.json')}.`
+        );
         console.log();
         console.log(`    ${chalk.dim('// ...')}`);
         console.log(`    ${chalk.yellow('"scripts"')}: {`);
         console.log(`      ${chalk.dim('// ...')}`);
-        console.log(`      ${chalk.yellow('"predeploy"')}: ${chalk.yellow('"npm run build",')}`);
-        console.log(`      ${chalk.yellow('"deploy"')}: ${chalk.yellow('"gh-pages -d build"')}`);
+        console.log(
+          `      ${chalk.yellow('"predeploy"')}: ${chalk.yellow('"npm run build",')}`
+        );
+        console.log(
+          `      ${chalk.yellow('"deploy"')}: ${chalk.yellow('"gh-pages -d build"')}`
+        );
         console.log('    }');
         console.log();
         console.log('Then run:');
@@ -135,29 +148,43 @@ function build(previousFileSizes) {
       console.log();
     } else if (publicPath !== '/') {
       // "homepage": "http://mywebsite.com/project"
-      console.log(`The project was built assuming it is hosted at ${chalk.green(publicPath)}.`);
-      console.log(`You can control this with the ${chalk.green('homepage')} field in your ${chalk.cyan('package.json')}.`);
+      console.log(
+        `The project was built assuming it is hosted at ${chalk.green(publicPath)}.`
+      );
+      console.log(
+        `You can control this with the ${chalk.green('homepage')} field in your ${chalk.cyan('package.json')}.`
+      );
       console.log();
       console.log(`The ${chalk.cyan('build')} folder is ready to be deployed.`);
       console.log();
     } else {
       if (publicUrl) {
         // "homepage": "http://mywebsite.com"
-        console.log(`The project was built assuming it is hosted at ${chalk.green(publicUrl)}.`);
-        console.log(`You can control this with the ${chalk.green('homepage')} field in your ${chalk.cyan('package.json')}.`);
+        console.log(
+          `The project was built assuming it is hosted at ${chalk.green(publicUrl)}.`
+        );
+        console.log(
+          `You can control this with the ${chalk.green('homepage')} field in your ${chalk.cyan('package.json')}.`
+        );
         console.log();
       } else {
         // no homepage
-        console.log('The project was built assuming it is hosted at the server root.');
-        console.log(`To override this, specify the ${chalk.green('homepage')} in your ${chalk.cyan('package.json')}.`);
-        console.log('For example, add this to build it for GitHub Pages:')
+        console.log(
+          'The project was built assuming it is hosted at the server root.'
+        );
+        console.log(
+          `To override this, specify the ${chalk.green('homepage')} in your ${chalk.cyan('package.json')}.`
+        );
+        console.log('For example, add this to build it for GitHub Pages:');
         console.log();
-        console.log(`  ${chalk.green('"homepage"')} ${chalk.cyan(':')} ${chalk.green('"http://myname.github.io/myapp"')}${chalk.cyan(',')}`);
+        console.log(
+          `  ${chalk.green('"homepage"')} ${chalk.cyan(':')} ${chalk.green('"http://myname.github.io/myapp"')}${chalk.cyan(',')}`
+        );
         console.log();
       }
       const build = path.relative(process.cwd(), paths.appBuild);
       console.log(`The ${chalk.cyan(build)} folder is ready to be deployed.`);
-      console.log('You may also serve it locally with a static server:')
+      console.log('You may also serve it locally with a static server:');
       console.log();
       if (useYarn) {
         console.log(`  ${chalk.cyan('yarn')} global add pushstate-server`);
@@ -165,7 +192,9 @@ function build(previousFileSizes) {
         console.log(`  ${chalk.cyan('npm')} install -g pushstate-server`);
       }
       console.log(`  ${chalk.cyan('pushstate-server')} build`);
-      console.log(`  ${chalk.cyan(openCommand)} http://localhost:${(process.env.PORT || 9000)}`);
+      console.log(
+        `  ${chalk.cyan(openCommand)} http://localhost:${process.env.PORT || 9000}`
+      );
       console.log();
     }
   });
@@ -174,6 +203,6 @@ function build(previousFileSizes) {
 function copyPublicFolder() {
   fs.copySync(paths.appPublic, paths.appBuild, {
     dereference: true,
-    filter: file => file !== paths.appHtml
+    filter: file => file !== paths.appHtml,
   });
 }
diff --git a/packages/react-scripts/scripts/eject.js b/packages/react-scripts/scripts/eject.js
index 5b801dd9bd9..68c43d25068 100644
--- a/packages/react-scripts/scripts/eject.js
+++ b/packages/react-scripts/scripts/eject.js
@@ -38,31 +38,30 @@ prompt(
     if (fs.existsSync(path.join(appPath, file))) {
       console.error(
         `\`${file}\` already exists in your app folder. We cannot ` +
-        'continue as you would lose all the changes in that file or directory. ' +
-        'Please move or delete it (maybe make a copy for backup) and run this ' +
-        'command again.'
+          'continue as you would lose all the changes in that file or directory. ' +
+          'Please move or delete it (maybe make a copy for backup) and run this ' +
+          'command again.'
       );
       process.exit(1);
     }
   }
 
-  const folders = [
-    'config',
-    'config/jest',
-    'scripts',
-    'scripts/utils',
-  ];
+  const folders = ['config', 'config/jest', 'scripts', 'scripts/utils'];
 
   // Make shallow array of files paths
-  const files = folders.reduce((files, folder) => {
-    return files.concat(
-      fs.readdirSync(path.join(ownPath, folder))
-        // set full path
-        .map(file => path.join(ownPath, folder, file))
-        // omit dirs from file list
-        .filter(file => fs.lstatSync(file).isFile())
-    );
-  }, []);
+  const files = folders.reduce(
+    (files, folder) => {
+      return files.concat(
+        fs
+          .readdirSync(path.join(ownPath, folder))
+          // set full path
+          .map(file => path.join(ownPath, folder, file))
+          // omit dirs from file list
+          .filter(file => fs.lstatSync(file).isFile())
+      );
+    },
+    []
+  );
 
   // Ensure that the app folder is clean and we won't override any files
   folders.forEach(verifyAbsent);
@@ -72,7 +71,7 @@ prompt(
   console.log(cyan(`Copying files into ${appPath}`));
 
   folders.forEach(folder => {
-    fs.mkdirSync(path.join(appPath, folder))
+    fs.mkdirSync(path.join(appPath, folder));
   });
 
   files.forEach(file => {
@@ -84,9 +83,15 @@ prompt(
     }
     content = content
       // Remove dead code from .js files on eject
-      .replace(/\/\/ @remove-on-eject-begin([\s\S]*?)\/\/ @remove-on-eject-end/mg, '')
+      .replace(
+        /\/\/ @remove-on-eject-begin([\s\S]*?)\/\/ @remove-on-eject-end/mg,
+        ''
+      )
       // Remove dead code from .applescript files on eject
-      .replace(/-- @remove-on-eject-begin([\s\S]*?)-- @remove-on-eject-end/mg, '')
+      .replace(
+        /-- @remove-on-eject-begin([\s\S]*?)-- @remove-on-eject-end/mg,
+        ''
+      )
       .trim() + '\n';
     console.log(`  Adding ${cyan(file.replace(ownPath, ''))} to the project`);
     fs.writeFileSync(file.replace(ownPath, appPath), content);
@@ -95,8 +100,12 @@ prompt(
 
   const ownPackage = require(path.join(ownPath, 'package.json'));
   const appPackage = require(path.join(appPath, 'package.json'));
-  const babelConfig = JSON.parse(fs.readFileSync(path.join(ownPath, '.babelrc'), 'utf8'));
-  const eslintConfig = JSON.parse(fs.readFileSync(path.join(ownPath, '.eslintrc'), 'utf8'));
+  const babelConfig = JSON.parse(
+    fs.readFileSync(path.join(ownPath, '.babelrc'), 'utf8')
+  );
+  const eslintConfig = JSON.parse(
+    fs.readFileSync(path.join(ownPath, '.eslintrc'), 'utf8')
+  );
 
   console.log(cyan('Updating the dependencies'));
   const ownPackageName = ownPackage.name;
@@ -123,8 +132,10 @@ prompt(
   Object.keys(appPackage.scripts).forEach(key => {
     Object.keys(ownPackage.bin).forEach(binKey => {
       const regex = new RegExp(binKey + ' (\\w+)', 'g');
-      appPackage.scripts[key] = appPackage.scripts[key]
-        .replace(regex, 'node scripts/$1.js');
+      appPackage.scripts[key] = appPackage.scripts[key].replace(
+        regex,
+        'node scripts/$1.js'
+      );
       console.log(
         `  Replacing ${cyan(`"${binKey} ${key}"`)} with ${cyan(`"node scripts/${key}.js"`)}`
       );
@@ -163,22 +174,22 @@ prompt(
         fs.removeSync(path.join(appPath, 'node_modules', '.bin', binKey));
       });
       fs.removeSync(ownPath);
-    } catch(e) {
+    } catch (e) {
       // It's not essential that this succeeds
     }
   }
 
   if (fs.existsSync(paths.yarnLockFile)) {
     console.log(cyan('Running yarn...'));
-    spawnSync('yarnpkg', [], {stdio: 'inherit'});
+    spawnSync('yarnpkg', [], { stdio: 'inherit' });
   } else {
     console.log(cyan('Running npm install...'));
-    spawnSync('npm', ['install'], {stdio: 'inherit'});
+    spawnSync('npm', ['install'], { stdio: 'inherit' });
   }
   console.log(green('Ejected successfully!'));
   console.log();
 
   console.log(green('Please consider sharing why you ejected in this survey:'));
   console.log(green('  http://goo.gl/forms/Bi6CZjk1EqsdelXk1'));
-  console.log()
-})
+  console.log();
+});
diff --git a/packages/react-scripts/scripts/init.js b/packages/react-scripts/scripts/init.js
index 39b39a68eec..b8a820c821d 100644
--- a/packages/react-scripts/scripts/init.js
+++ b/packages/react-scripts/scripts/init.js
@@ -14,8 +14,18 @@ const path = require('path');
 const spawn = require('cross-spawn');
 const chalk = require('chalk');
 
-module.exports = function(appPath, appName, verbose, originalDirectory, template) {
-  const ownPackageName = require(path.join(__dirname, '..', 'package.json')).name;
+module.exports = function(
+  appPath,
+  appName,
+  verbose,
+  originalDirectory,
+  template
+) {
+  const ownPackageName = require(path.join(
+    __dirname,
+    '..',
+    'package.json'
+  )).name;
   const ownPath = path.join(appPath, 'node_modules', ownPackageName);
   const appPackage = require(path.join(appPath, 'package.json'));
   const useYarn = fs.existsSync(path.join(appPath, 'yarn.lock'));
@@ -26,10 +36,10 @@ module.exports = function(appPath, appName, verbose, originalDirectory, template
 
   // Setup the script rules
   appPackage.scripts = {
-    'start': 'react-scripts start',
-    'build': 'react-scripts build',
-    'test': 'react-scripts test --env=jsdom',
-    'eject': 'react-scripts eject'
+    start: 'react-scripts start',
+    build: 'react-scripts build',
+    test: 'react-scripts test --env=jsdom',
+    eject: 'react-scripts eject',
   };
 
   fs.writeFileSync(
@@ -39,32 +49,44 @@ module.exports = function(appPath, appName, verbose, originalDirectory, template
 
   const readmeExists = fs.existsSync(path.join(appPath, 'README.md'));
   if (readmeExists) {
-    fs.renameSync(path.join(appPath, 'README.md'), path.join(appPath, 'README.old.md'));
+    fs.renameSync(
+      path.join(appPath, 'README.md'),
+      path.join(appPath, 'README.old.md')
+    );
   }
 
   // Copy the files for the user
-  const templatePath = template ? path.resolve(originalDirectory, template) : path.join(ownPath, 'template');
+  const templatePath = template
+    ? path.resolve(originalDirectory, template)
+    : path.join(ownPath, 'template');
   if (fs.existsSync(templatePath)) {
     fs.copySync(templatePath, appPath);
   } else {
-    console.error(`Could not locate supplied template: ${chalk.green(templatePath)}`);
+    console.error(
+      `Could not locate supplied template: ${chalk.green(templatePath)}`
+    );
     return;
   }
 
   // Rename gitignore after the fact to prevent npm from renaming it to .npmignore
   // See: https://github.com/npm/npm/issues/1862
-  fs.move(path.join(appPath, 'gitignore'), path.join(appPath, '.gitignore'), [],  err => {
-    if (err) {
-      // Append if there's already a `.gitignore` file there
-      if (err.code === 'EEXIST') {
-        const data = fs.readFileSync(path.join(appPath, 'gitignore'));
-        fs.appendFileSync(path.join(appPath, '.gitignore'), data);
-        fs.unlinkSync(path.join(appPath, 'gitignore'));
-      } else {
-        throw err;
+  fs.move(
+    path.join(appPath, 'gitignore'),
+    path.join(appPath, '.gitignore'),
+    [],
+    err => {
+      if (err) {
+        // Append if there's already a `.gitignore` file there
+        if (err.code === 'EEXIST') {
+          const data = fs.readFileSync(path.join(appPath, 'gitignore'));
+          fs.appendFileSync(path.join(appPath, '.gitignore'), data);
+          fs.unlinkSync(path.join(appPath, 'gitignore'));
+        } else {
+          throw err;
+        }
       }
     }
-  });
+  );
 
   let command;
   let args;
@@ -74,21 +96,22 @@ module.exports = function(appPath, appName, verbose, originalDirectory, template
     args = ['add'];
   } else {
     command = 'npm';
-    args = [
-      'install',
-      '--save',
-      verbose && '--verbose'
-    ].filter(e => e);
+    args = ['install', '--save', verbose && '--verbose'].filter(e => e);
   }
   args.push('react', 'react-dom');
 
   // Install additional template dependencies, if present
-  const templateDependenciesPath = path.join(appPath, '.template.dependencies.json');
+  const templateDependenciesPath = path.join(
+    appPath,
+    '.template.dependencies.json'
+  );
   if (fs.existsSync(templateDependenciesPath)) {
     const templateDependencies = require(templateDependenciesPath).dependencies;
-    args = args.concat(Object.keys(templateDependencies).map(key => {
-      return `${key}@${templateDependencies[key]}`;
-    }));
+    args = args.concat(
+      Object.keys(templateDependencies).map(key => {
+        return `${key}@${templateDependencies[key]}`;
+      })
+    );
     fs.unlinkSync(templateDependenciesPath);
   }
 
@@ -99,7 +122,7 @@ module.exports = function(appPath, appName, verbose, originalDirectory, template
     console.log(`Installing react and react-dom using ${command}...`);
     console.log();
 
-    const proc = spawn.sync(command, args, {stdio: 'inherit'});
+    const proc = spawn.sync(command, args, { stdio: 'inherit' });
     if (proc.status !== 0) {
       console.error(`\`${command} ${args.join(' ')}\` failed`);
       return;
@@ -110,8 +133,7 @@ module.exports = function(appPath, appName, verbose, originalDirectory, template
   // This needs to handle an undefined originalDirectory for
   // backward compatibility with old global-cli's.
   let cdpath;
-  if (originalDirectory &&
-      path.join(originalDirectory, appName) === appPath) {
+  if (originalDirectory && path.join(originalDirectory, appName) === appPath) {
     cdpath = appName;
   } else {
     cdpath = appPath;
@@ -134,8 +156,12 @@ module.exports = function(appPath, appName, verbose, originalDirectory, template
   console.log('    Starts the test runner.');
   console.log();
   console.log(chalk.cyan(`  ${displayedCommand} run eject`));
-  console.log('    Removes this tool and copies build dependencies, configuration files');
-  console.log('    and scripts into the app directory. If you do this, you can’t go back!');
+  console.log(
+    '    Removes this tool and copies build dependencies, configuration files'
+  );
+  console.log(
+    '    and scripts into the app directory. If you do this, you can’t go back!'
+  );
   console.log();
   console.log('We suggest that you begin by typing:');
   console.log();
@@ -143,7 +169,11 @@ module.exports = function(appPath, appName, verbose, originalDirectory, template
   console.log(`  ${chalk.cyan(`${displayedCommand} start`)}`);
   if (readmeExists) {
     console.log();
-    console.log(chalk.yellow('You had a `README.md` file, we renamed it to `README.old.md`'));
+    console.log(
+      chalk.yellow(
+        'You had a `README.md` file, we renamed it to `README.old.md`'
+      )
+    );
   }
   console.log();
   console.log('Happy hacking!');
@@ -152,8 +182,6 @@ module.exports = function(appPath, appName, verbose, originalDirectory, template
 function isReactInstalled(appPackage) {
   const dependencies = appPackage.dependencies || {};
 
-  return (
-    typeof dependencies.react !== 'undefined' &&
-    typeof dependencies['react-dom'] !== 'undefined'
-  )
+  return typeof dependencies.react !== 'undefined' &&
+    typeof dependencies['react-dom'] !== 'undefined';
 }
diff --git a/packages/react-scripts/scripts/start.js b/packages/react-scripts/scripts/start.js
index 8a66043afa2..142a1f6d705 100644
--- a/packages/react-scripts/scripts/start.js
+++ b/packages/react-scripts/scripts/start.js
@@ -16,7 +16,7 @@ process.env.NODE_ENV = 'development';
 // if this file is missing. dotenv will never modify any environment variables
 // that have already been set.
 // https://github.com/motdotla/dotenv
-require('dotenv').config({silent: true});
+require('dotenv').config({ silent: true });
 
 const fs = require('fs');
 const chalk = require('chalk');
@@ -50,19 +50,24 @@ function run(port) {
   const host = process.env.HOST || 'localhost';
 
   // Create a webpack compiler that is configured with custom messages.
-  const compiler = createWebpackCompiler(config, function onReady(showInstructions) {
-    if (!showInstructions) {
-      return;
+  const compiler = createWebpackCompiler(
+    config,
+    function onReady(showInstructions) {
+      if (!showInstructions) {
+        return;
+      }
+      console.log();
+      console.log('The app is running at:');
+      console.log();
+      console.log(`  ${chalk.cyan(`${protocol}://${host}:${port}/`)}`);
+      console.log();
+      console.log('Note that the development build is not optimized.');
+      console.log(
+        `To create a production build, use ${chalk.cyan(`${cli} run build`)}.`
+      );
+      console.log();
     }
-    console.log();
-    console.log('The app is running at:');
-    console.log();
-    console.log(`  ${chalk.cyan(`${protocol}://${host}:${port}/`)}`);
-    console.log();
-    console.log('Note that the development build is not optimized.');
-    console.log(`To create a production build, use ${chalk.cyan(`${cli} run build`)}.`);
-    console.log();
-  });
+  );
 
   // Serve webpack assets generated by the compiler over a web sever.
   const devServer = new WebpackDevServer(compiler, devServerConfig);
@@ -97,9 +102,10 @@ detect(DEFAULT_PORT).then(port => {
   if (isInteractive) {
     clearConsole();
     const existingProcess = getProcessForPort(DEFAULT_PORT);
-    const question = chalk.yellow(`Something is already running on port ${DEFAULT_PORT}.` +
-      `${existingProcess ? ` Probably:\n  ${existingProcess}` : ''}`) +
-      '\n\nWould you like to run the app on another port instead?';
+    const question = chalk.yellow(
+      `Something is already running on port ${DEFAULT_PORT}.` +
+        `${existingProcess ? ` Probably:\n  ${existingProcess}` : ''}`
+    ) + '\n\nWould you like to run the app on another port instead?';
 
     prompt(question, true).then(shouldChangePort => {
       if (shouldChangePort) {
@@ -107,6 +113,8 @@ detect(DEFAULT_PORT).then(port => {
       }
     });
   } else {
-    console.log(chalk.red(`Something is already running on port ${DEFAULT_PORT}.`));
+    console.log(
+      chalk.red(`Something is already running on port ${DEFAULT_PORT}.`)
+    );
   }
 });
diff --git a/packages/react-scripts/scripts/test.js b/packages/react-scripts/scripts/test.js
index 7ff6a8f014f..e3a0094f982 100644
--- a/packages/react-scripts/scripts/test.js
+++ b/packages/react-scripts/scripts/test.js
@@ -17,7 +17,7 @@ process.env.PUBLIC_URL = '';
 // if this file is missing. dotenv will never modify any environment variables
 // that have already been set.
 // https://github.com/motdotla/dotenv
-require('dotenv').config({silent: true});
+require('dotenv').config({ silent: true });
 
 const jest = require('jest');
 const argv = process.argv.slice(2);
@@ -32,10 +32,15 @@ if (!process.env.CI && argv.indexOf('--coverage') < 0) {
 const createJestConfig = require('./utils/createJestConfig');
 const path = require('path');
 const paths = require('../config/paths');
-argv.push('--config', JSON.stringify(createJestConfig(
-  relativePath => path.resolve(__dirname, '..', relativePath),
-  path.resolve(paths.appSrc, '..'),
-  false
-)));
+argv.push(
+  '--config',
+  JSON.stringify(
+    createJestConfig(
+      relativePath => path.resolve(__dirname, '..', relativePath),
+      path.resolve(paths.appSrc, '..'),
+      false
+    )
+  )
+);
 // @remove-on-eject-end
 jest.run(argv);
diff --git a/packages/react-scripts/scripts/utils/addWebpackMiddleware.js b/packages/react-scripts/scripts/utils/addWebpackMiddleware.js
index 7fce6fbafef..d2a97507237 100644
--- a/packages/react-scripts/scripts/utils/addWebpackMiddleware.js
+++ b/packages/react-scripts/scripts/utils/addWebpackMiddleware.js
@@ -21,50 +21,73 @@ function onProxyError(proxy) {
   return (err, req, res) => {
     const host = req.headers && req.headers.host;
     console.log(
-      chalk.red('Proxy error:') + ' Could not proxy request ' + chalk.cyan(req.url) +
-      ' from ' + chalk.cyan(host) + ' to ' + chalk.cyan(proxy) + '.'
+      chalk.red('Proxy error:') +
+        ' Could not proxy request ' +
+        chalk.cyan(req.url) +
+        ' from ' +
+        chalk.cyan(host) +
+        ' to ' +
+        chalk.cyan(proxy) +
+        '.'
     );
     console.log(
       'See https://nodejs.org/api/errors.html#errors_common_system_errors for more information (' +
-      chalk.cyan(err.code) + ').'
+        chalk.cyan(err.code) +
+        ').'
     );
     console.log();
 
     // And immediately send the proper error response to the client.
     // Otherwise, the request will eventually timeout with ERR_EMPTY_RESPONSE on the client side.
     if (res.writeHead && !res.headersSent) {
-        res.writeHead(500);
+      res.writeHead(500);
     }
-    res.end('Proxy error: Could not proxy request ' + req.url + ' from ' +
-      host + ' to ' + proxy + ' (' + err.code + ').'
+    res.end(
+      'Proxy error: Could not proxy request ' +
+        req.url +
+        ' from ' +
+        host +
+        ' to ' +
+        proxy +
+        ' (' +
+        err.code +
+        ').'
     );
-  }
+  };
 }
 
 module.exports = function addWebpackMiddleware(devServer) {
   // `proxy` lets you to specify a fallback server during development.
   // Every unrecognized request will be forwarded to it.
   const proxy = require(paths.appPackageJson).proxy;
-  devServer.use(historyApiFallback({
-    // Paths with dots should still use the history fallback.
-    // See https://github.com/facebookincubator/create-react-app/issues/387.
-    disableDotRule: true,
-    // For single page apps, we generally want to fallback to /index.html.
-    // However we also want to respect `proxy` for API calls.
-    // So if `proxy` is specified, we need to decide which fallback to use.
-    // We use a heuristic: if request `accept`s text/html, we pick /index.html.
-    // Modern browsers include text/html into `accept` header when navigating.
-    // However API calls like `fetch()` won’t generally accept text/html.
-    // If this heuristic doesn’t work well for you, don’t use `proxy`.
-    htmlAcceptHeaders: proxy ?
-      ['text/html'] :
-      ['text/html', '*/*']
-  }));
+  devServer.use(
+    historyApiFallback({
+      // Paths with dots should still use the history fallback.
+      // See https://github.com/facebookincubator/create-react-app/issues/387.
+      disableDotRule: true,
+      // For single page apps, we generally want to fallback to /index.html.
+      // However we also want to respect `proxy` for API calls.
+      // So if `proxy` is specified, we need to decide which fallback to use.
+      // We use a heuristic: if request `accept`s text/html, we pick /index.html.
+      // Modern browsers include text/html into `accept` header when navigating.
+      // However API calls like `fetch()` won’t generally accept text/html.
+      // If this heuristic doesn’t work well for you, don’t use `proxy`.
+      htmlAcceptHeaders: proxy ? ['text/html'] : ['text/html', '*/*'],
+    })
+  );
   if (proxy) {
     if (typeof proxy !== 'string') {
-      console.log(chalk.red('When specified, "proxy" in package.json must be a string.'));
-      console.log(chalk.red('Instead, the type of "proxy" was "' + typeof proxy + '".'));
-      console.log(chalk.red('Either remove "proxy" from package.json, or make it a string.'));
+      console.log(
+        chalk.red('When specified, "proxy" in package.json must be a string.')
+      );
+      console.log(
+        chalk.red('Instead, the type of "proxy" was "' + typeof proxy + '".')
+      );
+      console.log(
+        chalk.red(
+          'Either remove "proxy" from package.json, or make it a string.'
+        )
+      );
       process.exit(1);
     }
 
@@ -93,7 +116,7 @@ module.exports = function addWebpackMiddleware(devServer) {
       secure: false,
       changeOrigin: true,
       ws: true,
-      xfwd: true
+      xfwd: true,
     });
     devServer.use(mayProxy, hpm);
 
diff --git a/packages/react-scripts/scripts/utils/createJestConfig.js b/packages/react-scripts/scripts/utils/createJestConfig.js
index 6eab4d7ad5d..5ba7fd16cb2 100644
--- a/packages/react-scripts/scripts/utils/createJestConfig.js
+++ b/packages/react-scripts/scripts/utils/createJestConfig.js
@@ -15,7 +15,9 @@ const paths = require('../../config/paths');
 module.exports = (resolve, rootDir, isEjecting) => {
   // Use this instead of `paths.testsSetup` to avoid putting
   // an absolute filename into configuration after ejecting.
-  const setupTestsFile = fs.existsSync(paths.testsSetup) ? '<rootDir>/src/setupTests.js' : undefined;
+  const setupTestsFile = fs.existsSync(paths.testsSetup)
+    ? '<rootDir>/src/setupTests.js'
+    : undefined;
 
   // TODO: I don't know if it's safe or not to just use / as path separator
   // in Jest configs. We need help from somebody with Windows to determine this.
@@ -24,23 +26,21 @@ module.exports = (resolve, rootDir, isEjecting) => {
     setupFiles: [resolve('config/polyfills.js')],
     setupTestFrameworkScriptFile: setupTestsFile,
     testPathIgnorePatterns: [
-      '<rootDir>[/\\\\](build|docs|node_modules|scripts)[/\\\\]'
+      '<rootDir>[/\\\\](build|docs|node_modules|scripts)[/\\\\]',
     ],
     testEnvironment: 'node',
     testURL: 'http://localhost',
     transform: {
-      '^.+\\.(js|jsx)$': isEjecting ?
-        '<rootDir>/node_modules/babel-jest'
+      '^.+\\.(js|jsx)$': isEjecting
+        ? '<rootDir>/node_modules/babel-jest'
         : resolve('config/jest/babelTransform.js'),
       '^.+\\.css$': resolve('config/jest/cssTransform.js'),
       '^(?!.*\\.(js|jsx|css|json)$)': resolve('config/jest/fileTransform.js'),
     },
-    transformIgnorePatterns: [
-      '[/\\\\]node_modules[/\\\\].+\\.(js|jsx)$'
-    ],
+    transformIgnorePatterns: ['[/\\\\]node_modules[/\\\\].+\\.(js|jsx)$'],
     moduleNameMapper: {
-      '^react-native$': 'react-native-web'
-    }
+      '^react-native$': 'react-native-web',
+    },
   };
   if (rootDir) {
     config.rootDir = rootDir;
diff --git a/packages/react-scripts/scripts/utils/createWebpackCompiler.js b/packages/react-scripts/scripts/utils/createWebpackCompiler.js
index a06dc375fda..a333165b082 100644
--- a/packages/react-scripts/scripts/utils/createWebpackCompiler.js
+++ b/packages/react-scripts/scripts/utils/createWebpackCompiler.js
@@ -60,7 +60,7 @@ module.exports = function createWebpackCompiler(config, onReadyCallback) {
 
   // "done" event fires when Webpack has finished recompiling the bundle.
   // Whether or not you have warnings or errors, you will get this event.
-  compiler.plugin('done', (stats) => {
+  compiler.plugin('done', stats => {
     if (isInteractive) {
       clearConsole();
     }
@@ -102,8 +102,16 @@ module.exports = function createWebpackCompiler(config, onReadyCallback) {
       });
       // Teach some ESLint tricks.
       console.log('You may use special comments to disable some warnings.');
-      console.log('Use ' + chalk.yellow('// eslint-disable-next-line') + ' to ignore the next line.');
-      console.log('Use ' + chalk.yellow('/* eslint-disable */') + ' to ignore all warnings in a file.');
+      console.log(
+        'Use ' +
+          chalk.yellow('// eslint-disable-next-line') +
+          ' to ignore the next line.'
+      );
+      console.log(
+        'Use ' +
+          chalk.yellow('/* eslint-disable */') +
+          ' to ignore all warnings in a file.'
+      );
     }
   });
 
diff --git a/packages/react-scripts/template/src/index.js b/packages/react-scripts/template/src/index.js
index 54c5ef1a427..5d76a18a853 100644
--- a/packages/react-scripts/template/src/index.js
+++ b/packages/react-scripts/template/src/index.js
@@ -3,7 +3,4 @@ import ReactDOM from 'react-dom';
 import App from './App';
 import './index.css';
 
-ReactDOM.render(
-  <App />,
-  document.getElementById('root')
-);
+ReactDOM.render(<App />, document.getElementById('root'));