Use strict namespace behavior for mjs files. (#7545)

packages/babel-helper-module-transforms/src/index.js

@@ -22,7 +22,16 @@ export { hasExports, isSideEffectImport, isModule };
  */
 export function rewriteModuleStatementsAndPrepareHeader(
   path: NodePath,
-  { exportName, strict, allowTopLevelThis, strictMode, loose, noInterop, lazy },
+  {
+    exportName,
+    strict,
+    allowTopLevelThis,
+    strictMode,
+    loose,
+    noInterop,
+    lazy,
+    esNamespaceOnly,
+  },
 ) {
   assert(isModule(path), "Cannot process module statements in a script");
   path.node.sourceType = "script";
@@ -31,6 +40,7 @@ export function rewriteModuleStatementsAndPrepareHeader(
     noInterop,
     loose,
     lazy,
+    esNamespaceOnly,
   });
 
   if (!allowTopLevelThis) {

packages/babel-helper-module-transforms/src/normalize-and-load-metadata.js

@@ -86,7 +86,12 @@ export function isSideEffectImport(source: SourceModuleMetadata) {
 export default function normalizeModuleAndLoadMetadata(
   programPath: NodePath,
   exportName?: string,
-  { noInterop = false, loose = false, lazy = false } = {},
+  {
+    noInterop = false,
+    loose = false,
+    lazy = false,
+    esNamespaceOnly = false,
+  } = {},
 ): ModuleMetadata {
   if (!exportName) {
     exportName = programPath.scope.generateUidIdentifier("exports").name;
@@ -107,6 +112,16 @@ export default function normalizeModuleAndLoadMetadata(
     }
 
     if (noInterop) metadata.interop = "none";
+    else if (esNamespaceOnly) {
+      // Both the default and namespace interops pass through __esModule
+      // objects, but the namespace interop is used to enable Babel's
+      // destructuring-like interop behavior for normal CommonJS.
+      // Since some tooling has started to remove that behavior, we expose
+      // it as the `esNamespace` option.
+      if (metadata.interop === "namespace") {
+        metadata.interop = "default";
+      }
+    }
   }
 
   return {

packages/babel-plugin-transform-classes/test/fixtures/regression/2775/output.js

@@ -5,7 +5,7 @@ Object.defineProperty(exports, "__esModule", {
 });
 exports.default = void 0;
 
-var _react = babelHelpers.interopRequireWildcard(require("react"));
+var _react = babelHelpers.interopRequireDefault(require("react"));
 
 var RandomComponent =
 /*#__PURE__*/

packages/babel-plugin-transform-modules-commonjs/src/index.js

@@ -15,6 +15,14 @@ export default declare((api, options) => {
 
   const {
     loose,
+
+    // 'true' for non-mjs files to strictly have .default, instead of having
+    // destructuring-like behavior for their properties.
+    strictNamespace = false,
+
+    // 'true' for mjs files to strictly have .default, instead of having
+    // destructuring-like behavior for their properties.
+    mjsStrictNamespace = true,
     allowTopLevelThis,
     strict,
     strictMode,
@@ -32,6 +40,13 @@ export default declare((api, options) => {
     throw new Error(`.lazy must be a boolean, array of strings, or a function`);
   }
 
+  if (typeof strictNamespace !== "boolean") {
+    throw new Error(`.strictNamespace must be a boolean, or undefined`);
+  }
+  if (typeof mjsStrictNamespace !== "boolean") {
+    throw new Error(`.mjsStrictNamespace must be a boolean, or undefined`);
+  }
+
   const getAssertion = localName => template.expression.ast`
     (function(){
       throw new Error(
@@ -103,7 +118,7 @@ export default declare((api, options) => {
   return {
     visitor: {
       Program: {
-        exit(path) {
+        exit(path, state) {
           if (!isModule(path)) return;
 
           // Rename the bindings auto-injected into the scope so there is no
@@ -137,6 +152,11 @@ export default declare((api, options) => {
               allowTopLevelThis,
               noInterop,
               lazy,
+              esNamespaceOnly:
+                typeof state.filename === "string" &&
+                /\.mjs$/.test(state.filename)
+                  ? mjsStrictNamespace
+                  : strictNamespace,
             },
           );
 

packages/babel-plugin-transform-modules-commonjs/test/fixtures/auxiliary-comment/overview/output.js

@@ -31,7 +31,7 @@ _foo2 = babelHelpers.interopRequireDefault(require("foo2"))
 
 var
 /*before*/
-foo2 = babelHelpers.interopRequireWildcard(require("foo3"))
+foo2 = babelHelpers.interopRequireDefault(require("foo3"))
 /*after*/
 ;
 

packages/babel-plugin-transform-modules-commonjs/test/fixtures/interop-loose/imports-hoisting/output.js

@@ -1,5 +1,9 @@
-var _taggedTemplateLiteral = require("@babel/runtime/helpers/taggedTemplateLiteral");
+"use strict";
 
-var _templateObject = /*#__PURE__*/ _taggedTemplateLiteral(["foo"]);
+var _interopRequireDefault = require("@babel/runtime/helpers/interopRequireDefault");
+
+var _taggedTemplateLiteral2 = _interopRequireDefault(require("@babel/runtime/helpers/taggedTemplateLiteral"));
+
+var _templateObject = /*#__PURE__*/ (0, _taggedTemplateLiteral2.default)(["foo"]);
 
 tag(_templateObject);

packages/babel-plugin-transform-modules-commonjs/test/fixtures/interop-loose/options.json

@@ -1,4 +1,5 @@
 {
+  "sourceType": "module",
   "plugins": [
     "external-helpers",
     ["transform-modules-commonjs", { "loose": true }]

packages/babel-plugin-transform-modules-commonjs/test/fixtures/interop/imports-hoisting/output.js

@@ -1,5 +1,9 @@
-var _taggedTemplateLiteral = require("@babel/runtime/helpers/taggedTemplateLiteral");
+"use strict";
 
-var _templateObject = /*#__PURE__*/ _taggedTemplateLiteral(["foo"]);
+var _interopRequireDefault = require("@babel/runtime/helpers/interopRequireDefault");
+
+var _taggedTemplateLiteral2 = _interopRequireDefault(require("@babel/runtime/helpers/taggedTemplateLiteral"));
+
+var _templateObject = /*#__PURE__*/ (0, _taggedTemplateLiteral2.default)(["foo"]);
 
 tag(_templateObject);

packages/babel-plugin-transform-modules-commonjs/test/fixtures/interop/options.json

@@ -1,3 +1,4 @@
 {
+  "sourceType": "module",
   "plugins": ["external-helpers", "transform-modules-commonjs"]
 }

packages/babel-plugin-transform-modules-commonjs/test/fixtures/lazy-dep/import-namespace/output.js

@@ -1,7 +1,7 @@
 "use strict";
 
 function foo() {
-  const data = babelHelpers.interopRequireWildcard(require("foo"));
+  const data = babelHelpers.interopRequireDefault(require("foo"));
 
   foo = function () {
     return data;

packages/babel-plugin-transform-modules-commonjs/test/fixtures/lazy-dep/reexport-namespace/output.js

@@ -6,7 +6,7 @@ Object.defineProperty(exports, "__esModule", {
 exports.namespace = void 0;
 
 function namespace() {
-  const data = babelHelpers.interopRequireWildcard(require("foo"));
+  const data = babelHelpers.interopRequireDefault(require("foo"));
 
   namespace = function () {
     return data;

packages/babel-plugin-transform-modules-commonjs/test/fixtures/lazy-local/import-namespace/output.js

@@ -1,4 +1,4 @@
 "use strict";
 
-var foo = babelHelpers.interopRequireWildcard(require("./foo"));
+var foo = babelHelpers.interopRequireDefault(require("./foo"));
 console.log(foo);

packages/babel-plugin-transform-modules-commonjs/test/fixtures/lazy-local/reexport-namespace/output.js

@@ -4,5 +4,5 @@ Object.defineProperty(exports, "__esModule", {
   value: true
 });
 exports.namespace = void 0;
-var namespace = babelHelpers.interopRequireWildcard(require("./foo"));
+var namespace = babelHelpers.interopRequireDefault(require("./foo"));
 exports.namespace = namespace;

packages/babel-plugin-transform-modules-commonjs/test/fixtures/lazy-whitelist/import-namespace/output.js

@@ -1,9 +1,9 @@
 "use strict";
 
-var foo1 = babelHelpers.interopRequireWildcard(require("white"));
+var foo1 = babelHelpers.interopRequireDefault(require("white"));
 
 function foo2() {
-  const data = babelHelpers.interopRequireWildcard(require("black"));
+  const data = babelHelpers.interopRequireDefault(require("black"));
 
   foo2 = function () {
     return data;

packages/babel-plugin-transform-modules-commonjs/test/fixtures/lazy-whitelist/reexport-namespace/output.js

@@ -4,11 +4,11 @@ Object.defineProperty(exports, "__esModule", {
   value: true
 });
 exports.namespace2 = exports.namespace1 = void 0;
-var namespace1 = babelHelpers.interopRequireWildcard(require("white"));
+var namespace1 = babelHelpers.interopRequireDefault(require("white"));
 exports.namespace1 = namespace1;
 
 function namespace2() {
-  const data = babelHelpers.interopRequireWildcard(require("black"));
+  const data = babelHelpers.interopRequireDefault(require("black"));
 
   namespace2 = function () {
     return data;

packages/babel-plugin-transform-modules-commonjs/test/fixtures/misc/copy-getters-setters-star/options.json

@@ -0,0 +1,5 @@
+{
+  "plugins": [
+    ["transform-modules-commonjs", { "mjsStrictNamespace": false }]
+  ]
+}

packages/babel-plugin-transform-modules-commonjs/test/fixtures/misc/copy-getters-setters/output.js

@@ -16,6 +16,6 @@ Object.defineProperty(exports, "baz", {
   }
 });
 
-var _moduleWithGetter = _interopRequireWildcard(require("./moduleWithGetter"));
+var _moduleWithGetter = _interopRequireDefault(require("./moduleWithGetter"));
 
-function _interopRequireWildcard(obj) { if (obj && obj.__esModule) { return obj; } else { var newObj = {}; if (obj != null) { for (var key in obj) { if (Object.prototype.hasOwnProperty.call(obj, key)) { var desc = Object.defineProperty && Object.getOwnPropertyDescriptor ? Object.getOwnPropertyDescriptor(obj, key) : {}; if (desc.get || desc.set) { Object.defineProperty(newObj, key, desc); } else { newObj[key] = obj[key]; } } } } newObj.default = obj; return newObj; } }
+function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

packages/babel-plugin-transform-modules-commonjs/test/fixtures/misc/import-const-throw/output.js

@@ -2,12 +2,10 @@
 
 var _foo = _interopRequireDefault(require("foo"));
 
-var Bar = _interopRequireWildcard(require("bar"));
+var Bar = _interopRequireDefault(require("bar"));
 
 var _baz = require("baz");
 
-function _interopRequireWildcard(obj) { if (obj && obj.__esModule) { return obj; } else { var newObj = {}; if (obj != null) { for (var key in obj) { if (Object.prototype.hasOwnProperty.call(obj, key)) { var desc = Object.defineProperty && Object.getOwnPropertyDescriptor ? Object.getOwnPropertyDescriptor(obj, key) : {}; if (desc.get || desc.set) { Object.defineProperty(newObj, key, desc); } else { newObj[key] = obj[key]; } } } } newObj.default = obj; return newObj; } }
-
 function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
 
 _foo.default = (42, function () {

packages/babel-plugin-transform-modules-commonjs/test/fixtures/misc/reference-source-map/output.js

@@ -6,7 +6,7 @@ var _two = require("two");
 
 var _three = require("three");
 
-var aNamespace = babelHelpers.interopRequireWildcard(require("four"));
+var aNamespace = babelHelpers.interopRequireDefault(require("four"));
 console.log(_one.default);
 console.log(_two.aNamed);
 console.log(_three.orig);

packages/babel-plugin-transform-modules-commonjs/test/fixtures/regression/lazy-7176/output.js

@@ -1,7 +1,7 @@
 "use strict";
 
 function mod() {
-  const data = babelHelpers.interopRequireWildcard(require("mod"));
+  const data = babelHelpers.interopRequireDefault(require("mod"));
 
   mod = function () {
     return data;

packages/babel-plugin-transform-modules-commonjs/test/fixtures/strict/options.json

@@ -2,6 +2,6 @@
   "plugins": [
     "external-helpers",
     "syntax-object-rest-spread",
-    ["transform-modules-commonjs", { "strict": true }]
+    ["transform-modules-commonjs", { "strict": true, "mjsStrictNamespace": false }]
   ]
 }