Merge pull request microsoft#3586 from vvakame/addEsModule

improve  module loading interoperability for babel

Author: JsonFreeman

src/compiler/emitter.ts

@@ -3012,6 +3012,26 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, Promi
                 return result;
             }
 
+            function emitEs6ExportDefaultCompat(node: Node) {
+                if (node.parent.kind === SyntaxKind.SourceFile) {
+                    Debug.assert(!!(node.flags & NodeFlags.Default) || node.kind === SyntaxKind.ExportAssignment);
+                    // only allow export default at a source file level
+                    if (compilerOptions.module === ModuleKind.CommonJS || compilerOptions.module === ModuleKind.AMD || compilerOptions.module === ModuleKind.UMD) {
+                        if (!currentSourceFile.symbol.exports["___esModule"]) {
+                            if (languageVersion === ScriptTarget.ES5) {
+                                // default value of configurable, enumerable, writable are `false`. 
+                                write("Object.defineProperty(exports, \"__esModule\", { value: true });");
+                                writeLine();
+                            }
+                            else if (languageVersion === ScriptTarget.ES3) {
+                                write("exports.__esModule = true;");
+                                writeLine();
+                            }
+                        }
+                    }
+                }
+            }
+
             function emitExportMemberAssignment(node: FunctionLikeDeclaration | ClassDeclaration) {
                 if (node.flags & NodeFlags.Export) {
                     writeLine();
@@ -3034,9 +3054,11 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, Promi
                     }
                     else {
                         if (node.flags & NodeFlags.Default) {
+                            emitEs6ExportDefaultCompat(node);
                             if (languageVersion === ScriptTarget.ES3) {
                                 write("exports[\"default\"]");
-                            } else {
+                            }
+                            else {
                                 write("exports.default");
                             }
                         }
@@ -5538,6 +5560,7 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, Promi
                             write(")");
                         }
                         else {
+                            emitEs6ExportDefaultCompat(node);
                             emitContainingModuleName(node);
                             if (languageVersion === ScriptTarget.ES3) {
                                 write("[\"default\"] = ");

tests/baselines/reference/es5-commonjs.js

@@ -0,0 +1,27 @@
+//// [es5-commonjs.ts]
+
+export default class A
+{
+    constructor ()
+    {
+
+    }
+
+    public B()
+    {
+        return 42;
+    }
+}
+
+
+//// [es5-commonjs.js]
+var A = (function () {
+    function A() {
+    }
+    A.prototype.B = function () {
+        return 42;
+    };
+    return A;
+})();
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.default = A;