chore: added type checking using comments

lib/utils/addEntries.js

@@ -3,6 +3,18 @@
 const webpack = require('webpack');
 const createDomain = require('./createDomain');
 
+/**
+ * A Entry, it can be of type string or string[] or Object<string | string[],string>
+ * @typedef {(string[] | string | Object<string | string[],string>)} Entry
+ */
+
+/**
+ * Add entries Method
+ * @param {?Object} config - Webpack config
+ * @param {?Object} options - Dev-Server options
+ * @param {?Object} server
+ * @returns {void}
+ */
 function addEntries(config, options, server) {
   if (options.inline !== false) {
     // we're stubbing the app in this method as it's static and doesn't require
@@ -15,21 +27,33 @@ function addEntries(config, options, server) {
       },
     };
 
+    /** @type {string} */
     const domain = createDomain(options, app);
+    /** @type {string} */
     const sockHost = options.sockHost ? `&sockHost=${options.sockHost}` : '';
+    /** @type {string} */
     const sockPath = options.sockPath ? `&sockPath=${options.sockPath}` : '';
+    /** @type {string} */
     const sockPort = options.sockPort ? `&sockPort=${options.sockPort}` : '';
+    /** @type {string} */
     const clientEntry = `${require.resolve(
       '../../client/'
     )}?${domain}${sockHost}${sockPath}${sockPort}`;
+
+    /** @type {(string[] | string)} */
     let hotEntry;
 
     if (options.hotOnly) {
       hotEntry = require.resolve('webpack/hot/only-dev-server');
     } else if (options.hot) {
       hotEntry = require.resolve('webpack/hot/dev-server');
     }
-
+    /**
+     * prependEntry Method
+     * @param {Entry} originalEntry
+     * @param {Entry} additionalEntries
+     * @returns {Entry}
+     */
     const prependEntry = (originalEntry, additionalEntries) => {
       if (typeof originalEntry === 'function') {
         return () =>
@@ -39,6 +63,7 @@ function addEntries(config, options, server) {
       }
 
       if (typeof originalEntry === 'object' && !Array.isArray(originalEntry)) {
+        /** @type {Object<string,string>} */
         const clone = {};
 
         Object.keys(originalEntry).forEach((key) => {
@@ -51,6 +76,7 @@ function addEntries(config, options, server) {
 
       // in this case, entry is a string or an array.
       // make sure that we do not add duplicates.
+      /** @type {Entry} */
       const entriesClone = additionalEntries.slice(0);
       [].concat(originalEntry).forEach((newEntry) => {
         if (!entriesClone.includes(newEntry)) {
@@ -60,21 +86,38 @@ function addEntries(config, options, server) {
       return entriesClone;
     };
 
+    /**
+     *
+     * Description of the option for checkInject method
+     * @typedef {Function} checkInjectOptionsParam
+     * @param {Object} _config - compilerConfig
+     * @return {Boolean}
+     */
+
+    /**
+     *
+     * @param {Boolean | checkInjectOptionsParam} option - inject(Hot|Client) it is Boolean | fn => Boolean
+     * @param {Object} _config
+     * @param {Boolean} defaultValue
+     * @return {Boolean}
+     */
     // eslint-disable-next-line no-shadow
-    const checkInject = (option, config, defaultValue) => {
+    const checkInject = (option, _config, defaultValue) => {
       if (typeof option === 'boolean') return option;
-      if (typeof option === 'function') return option(config);
+      if (typeof option === 'function') return option(_config);
       return defaultValue;
     };
 
     // eslint-disable-next-line no-shadow
     [].concat(config).forEach((config) => {
+      /** @type {Boolean} */
       const webTarget =
         config.target === 'web' ||
         config.target === 'webworker' ||
         config.target === 'electron-renderer' ||
         config.target === 'node-webkit' ||
         config.target == null;
+      /** @type {Entry} */
       const additionalEntries = checkInject(
         options.injectClient,
         config,

package.json

@@ -17,6 +17,7 @@
     "lint:prettier": "prettier \"{**/*,*}.{js,json,md,yml,css}\" --list-different",
     "lint:js": "eslint . --cache",
     "lint": "npm-run-all -l -p \"lint:**\"",
+    "lint:type": "tsc --noEmit",
     "commitlint": "commitlint --from=master",
     "security": "npm audit",
     "test:only": "jest",
@@ -106,6 +107,7 @@
     "style-loader": "^0.23.1",
     "supertest": "^4.0.2",
     "tcp-port-used": "^1.0.1",
+    "typescript": "^3.4.5",
     "url-loader": "^1.1.2",
     "webpack": "^4.35.2",
     "webpack-cli": "^3.3.5"

tsconfig.json

@@ -0,0 +1,16 @@
+{
+  "compilerOptions": {
+    "target": "ES2017",
+    "module": "commonjs",
+    "lib": ["es2017", "dom"],
+    "allowJs": true,
+    "checkJs": true,
+    "noEmit": true,
+    "strict": false,
+    "noImplicitThis": true,
+    "alwaysStrict": true,
+    "types": ["node"],
+    "esModuleInterop": true
+  },
+  "include": ["lib/utils/addEntries.js"]
+}