fix: have a local version of the exports patch

.eslintignore

@@ -4,3 +4,4 @@ documentation/*
 node_modules/*
 docs/*
 esm/*
+src/5to6-codemod

package.json

@@ -75,6 +75,7 @@
   },
   "config": {
     "cjs2esm": {
+      "ignore": ["5to6-codemod"],
       "filesWithShebang": [
         "src/bin.js"
       ]

src/5to6-codemod/exports.js

@@ -0,0 +1,259 @@
+/**
+ * exports - Replace module.exports calls with es6 exports
+ */
+
+var util = require('5to6-codemod/utils/main');
+
+module.exports = function (file, api, options) {
+  var j = api.jscodeshift;
+  var root = j(file.source);
+  var firstNode = root.find(j.Program).get('body', 0).node;
+
+  /**
+   * Move `module.exports.thing()` to `thing()`
+   */
+  function exportsCall(p) {
+    var functionCall = j.callExpression(p.value.callee.property, p.value.arguments);
+    // console.log(util.toString(p), '=>', util.toString(functionCall));
+    functionCall.comments = p.comments;
+    j(p).replaceWith(functionCall);
+  }
+
+  /**
+   * Must be run before exportsToExport
+   * ```
+   * module.exports.foo = foo
+   * module.exports.bar = bar
+   * exports.baz = baz
+   * to
+   * export { foo, bar, baz }
+   * ```
+   */
+  function MultiExportsToExport(paths) {
+    var specifiers = [];
+    var filteredPaths = paths.filter(function (p) {
+      if (p.parentPath.parentPath.name !== 'body') return false;
+
+      var isModuleExport =
+        p.get('left', 'object', 'object', 'name').value === 'module' &&
+        p.get('left', 'object', 'property', 'name').value === 'exports';
+      var isExport = p.get('left', 'object', 'name').value === 'exports';
+
+      if (!isModuleExport && !isExport) return false;
+
+      return p.value.left.property.name === p.value.right.name;
+    });
+    filteredPaths.forEach(function (p, i) {
+      // aggregate all specifiers
+      specifiers.push(
+        j.exportSpecifier.from({
+          exported: j.identifier(p.value.right.name),
+          local: j.identifier(p.value.right.name),
+        }),
+      );
+
+      // replace the last module.exports.*
+      if (i === filteredPaths.length - 1) {
+        j(p.parentPath).replaceWith(j.exportDeclaration(false, null, specifiers));
+      } else {
+        j(p.parentPath).remove();
+      }
+    });
+  }
+
+  /**
+   * Move `module.exports.thing` to `export const thing`
+   */
+  function exportsToExport(p) {
+    var declator = j.variableDeclarator(
+      j.identifier(p.value.left.property.name),
+      p.value.right,
+    );
+    var declaration = j.variableDeclaration('const', [declator]);
+    var exportDecl = j.exportDeclaration(false, declaration);
+    // console.log('[module.]exports.thing', util.toString(p), util.toString(exportDecl));
+    exportDecl.comments = p.parentPath.value.comments;
+    j(p.parentPath).replaceWith(exportDecl);
+  }
+
+  /**
+   * Move exports = module.exports to export default
+   */
+  function exportsAndModuleExportsToDefault(p) {
+    var exportDecl = j.exportDeclaration(true, p.value.right.right);
+    // console.log('exports = module.exports', util.toString(p.value.right.right), util.toString(exportDecl));
+    exportDecl.comments = p.parentPath.value.comments;
+    j(p.parentPath).replaceWith(exportDecl);
+  }
+
+  /**
+   * Move `module.exports` to `export default`
+   */
+  function exportsToDefault(p) {
+    var exportDecl = j.exportDeclaration(true, p.value.right);
+    // console.log('module.exports', util.toString(p), util.toString(exportDecl));
+    exportDecl.comments = p.parentPath.value.comments;
+    j(p.parentPath).replaceWith(exportDecl);
+  }
+
+  // find module.exports.thing = thing...
+  // find exports.thing = thing...
+  MultiExportsToExport(
+    root.find(j.AssignmentExpression, {
+      operator: '=',
+      left: {
+        type: 'MemberExpression',
+      },
+      right: {
+        type: 'Identifier',
+      },
+    }),
+  );
+
+  // find module.exports.thing = something....
+  root
+    .find(j.AssignmentExpression, {
+      operator: '=',
+      left: {
+        type: 'MemberExpression',
+        object: {
+          type: 'MemberExpression',
+          object: {
+            name: 'module',
+          },
+          property: { name: 'exports' },
+        },
+      },
+    })
+    .filter(function (p) {
+      return p.parentPath.parentPath.name === 'body';
+    })
+    .forEach(exportsToExport);
+
+  // find var House = module.exports = something....
+  root
+    .find(j.AssignmentExpression, {
+      operator: '=',
+      left: {
+        object: { name: 'module' },
+        property: { name: 'exports' },
+      },
+    })
+    .filter(function (p) {
+      var isVar = p.parentPath.value.type === 'VariableDeclarator';
+      var isOnBody = p.parentPath.parentPath.parentPath.parentPath.name === 'body';
+      return isVar && isOnBody;
+    })
+    .forEach(function (p) {
+      var decl = j.variableDeclarator(p.parentPath.value.id, p.value.right);
+      var exportDecl = j.exportDeclaration(true, p.parentPath.value.id);
+      // console.log(util.toString(decl), '\n', util.toString(exportDecl));
+      j(p.parentPath).replaceWith(decl);
+      j(p.parentPath.parentPath.parentPath).insertAfter(exportDecl);
+    });
+
+  // find module.exports = something....
+  root
+    .find(j.AssignmentExpression, {
+      operator: '=',
+      left: {
+        object: { name: 'module' },
+        property: { name: 'exports' },
+      },
+    })
+    .filter(function (p) {
+      return p.parentPath.parentPath.name === 'body';
+    })
+    .forEach(exportsToDefault);
+
+  // find exports.thing = something....
+  root
+    .find(j.AssignmentExpression, {
+      operator: '=',
+      left: {
+        object: { name: 'exports' },
+      },
+    })
+    .filter(function (p) {
+      return p.parentPath.parentPath.name === 'body';
+    })
+    .forEach(exportsToExport);
+
+  // find exports = module.exports = something....
+  root
+    .find(j.AssignmentExpression, {
+      operator: '=',
+      left: {
+        name: 'exports',
+      },
+      right: {
+        type: 'AssignmentExpression',
+        operator: '=',
+        left: {
+          type: 'MemberExpression',
+          object: {
+            name: 'module',
+          },
+          property: {
+            name: 'exports',
+          },
+        },
+      },
+    })
+    .filter(function (p) {
+      return p.parentPath.parentPath.name === 'body';
+    })
+    .forEach(exportsAndModuleExportsToDefault);
+
+  // find exports.house()
+  root
+    .find(j.CallExpression, {
+      callee: {
+        type: 'MemberExpression',
+        object: { name: 'exports' },
+      },
+    })
+    .forEach(exportsCall);
+
+  // find module.exports.house()
+  root
+    .find(j.CallExpression, {
+      callee: {
+        type: 'MemberExpression',
+        object: {
+          type: 'MemberExpression',
+          object: { name: 'module' },
+          property: { name: 'exports' },
+        },
+      },
+    })
+    .forEach(exportsCall);
+
+  // find var House = module.exports something....
+  root
+    .find(j.AssignmentExpression, {
+      operator: '=',
+      left: {
+        type: 'MemberExpression',
+        object: {
+          type: 'MemberExpression',
+          object: {
+            name: 'module',
+          },
+          property: { name: 'exports' },
+        },
+      },
+    })
+    .filter(function (p) {
+      return p.parentPath.parentPath.name === 'body';
+    })
+    .forEach(exportsToExport);
+
+  // re-add comment to to the top if necessary
+  var firstNode2 = root.find(j.Program).get('body', 0).node;
+  if (firstNode !== firstNode2) {
+    firstNode2.comments = firstNode.leadingComments;
+  }
+
+  return root.toSource(util.getRecastConfig(options));
+};

src/index.js

@@ -9,8 +9,16 @@ const { log, findFile, getAbsPathInfo, requireModule } = require('./utils');
  * this module does.
  *
  * @type {string}
+ * @ignore
  */
 const CJS2ESM_TRANSFORMATION_NAME = '<cjs2esm>';
+/**
+ * A list of 5to6-codemod transformations that are executed from local patches.
+ *
+ * @type {string[]}
+ * @ignore
+ */
+const CODEMOD_PATCHED_TRANSFORMATIONS = ['exports'];
 /**
  * This is called every time an unexpected error is thrown; it logs the error using the
  * `log`
@@ -364,29 +372,37 @@ const transformOutput = async (files, options) => {
 
   const cwd = process.cwd();
   let filepathForResolve;
+  let canUsePatch = false;
   if (codemodOptions.path) {
     filepathForResolve = path.join(cwd, codemodOptions.path, fileForResolve);
   } else {
+    canUsePatch = true;
     filepathForResolve = require.resolve(
       path.join('5to6-codemod', 'transforms', fileForResolve),
     );
   }
 
   const codeModPath = path.dirname(filepathForResolve);
   const transformations = codemodFiles.map((file, index) => {
-    if (index === fileForResolveIndex) {
-      return filepathForResolve;
-    }
     if (file === CJS2ESM_TRANSFORMATION_NAME) {
       return path.join(__dirname, 'transformer.js');
     }
 
     const fileWithExt = `${file}.js`;
+
+    if (canUsePatch && CODEMOD_PATCHED_TRANSFORMATIONS.includes(file)) {
+      return path.join(__dirname, '5to6-codemod', fileWithExt);
+    }
+
+    if (index === fileForResolveIndex) {
+      return filepathForResolve;
+    }
+
     if (fileWithExt.startsWith('.')) {
       return path.resolve(fileWithExt);
     }
 
-    return path.join(codeModPath, `${file}.js`);
+    return path.join(codeModPath, fileWithExt);
   });
 
   log('yellow', `Transforming ${files.length} files...`);