microsoft · DanielRosenwasser · Aug 10, 2020 · Jul 29, 2020 · Jul 30, 2020
diff --git a/src/compiler/factory/utilities.ts b/src/compiler/factory/utilities.ts
@@ -490,7 +490,7 @@ namespace ts {
      */
     export function getLocalNameForExternalImport(factory: NodeFactory, node: ImportDeclaration | ExportDeclaration | ImportEqualsDeclaration, sourceFile: SourceFile): Identifier | undefined {
         const namespaceDeclaration = getNamespaceDeclarationNode(node);
-        if (namespaceDeclaration && !isDefaultImport(node)) {
+        if (namespaceDeclaration && !isDefaultImport(node) && !isExportNamespaceAsDefaultDeclaration(node)) {
             const name = namespaceDeclaration.name;
             return isGeneratedIdentifier(name) ? name : factory.createIdentifier(getSourceTextOfNodeFromSourceFile(sourceFile, name) || idText(name));
         }

diff --git a/src/compiler/parser.ts b/src/compiler/parser.ts
@@ -6996,7 +6996,7 @@ namespace ts {
         }
 
         function parseNamespaceExport(pos: number): NamespaceExport {
-            return finishNode(factory.createNamespaceExport(parseIdentifier()), pos);
+            return finishNode(factory.createNamespaceExport(parseIdentifierName()), pos);
         }
 
         function parseExportDeclaration(pos: number, hasJSDoc: boolean, decorators: NodeArray<Decorator> | undefined, modifiers: NodeArray<Modifier> | undefined): ExportDeclaration {

diff --git a/src/compiler/transformers/module/esnextAnd2015.ts b/src/compiler/transformers/module/esnextAnd2015.ts
@@ -99,7 +99,7 @@ namespace ts {
             );
             setOriginalNode(importDecl, node.exportClause);
 
-            const exportDecl = factory.createExportDeclaration(
+            const exportDecl = isExportNamespaceAsDefaultDeclaration(node) ? factory.createExportDefault(synthName) : factory.createExportDeclaration(
                 /*decorators*/ undefined,
  
10000
               /*modifiers*/ undefined,
                 /*isTypeOnly*/ false,

diff --git a/src/compiler/transformers/module/module.ts b/src/compiler/transformers/module/module.ts
@@ -1043,6 +1043,7 @@ namespace ts {
             else if (node.exportClause) {
                 const statements: Statement[] = [];
                 // export * as ns from "mod";
+                // export * as default from "mod";
                 statements.push(
                     setOriginalNode(
                         setTextRange(
@@ -1051,7 +1052,8 @@ namespace ts {
                                     factory.cloneNode(node.exportClause.name),
                                     getHelperExpressionForExport(node, moduleKind !== ModuleKind.AMD ?
                                         createRequireCall(node) :
-                                        factory.createIdentifier(idText(node.exportClause.name)))
+                                        isExportNamespaceAsDefaultDeclaration(node) ? generatedName :
+                                            factory.createIdentifier(idText(node.exportClause.name)))
                                 )
                             ),
                             node

diff --git a/src/compiler/utilities.ts b/src/compiler/utilities.ts
@@ -518,6 +518,10 @@ namespace ts {
         return !!findAncestor(node, isJSDocTypeExpression);
     }
 
+    export function isExportNamespaceAsDefaultDeclaration(node: Node): boolean {
+        return !!(isExportDeclaration(node) && node.exportClause && isNamespaceExport(node.exportClause) && node.exportClause.name.escapedText === "default");
+    }
+
     export function getTextOfNodeFromSourceText(sourceText: string, node: Node, includeTrivia = false): string {
         if (nodeIsMissing(node)) {
             return "";

diff --git a/tests/baselines/reference/exportAsNamespace4(module=amd).js b/tests/baselines/reference/exportAsNamespace4(module=amd).js
@@ -0,0 +1,109 @@
+//// [tests/cases/conformance/es2020/modules/exportAsNamespace4.ts] ////
+
+//// [0.ts]
+export const a = 1;
+export const b = 2;
+
+//// [1.ts]
+export * as default from './0';
+
+//// [11.ts]
+import * as ns from './0';
+export default ns;
+
+//// [2.ts]
+import foo from './1'
+import foo1 from './11'
+
+foo.a;
+foo1.a;
+
+foo.b;
+foo1.b;
+
+//// [0.js]
+define(["require", "exports"], function (require, exports) {
+    "use strict";
+    exports.__esModule = true;
+    exports.b = exports.a = void 0;
+    exports.a = 1;
+    exports.b = 2;
+});
+//// [1.js]
+var __createBinding = (this && this.__createBinding) || (Object.create ? (function(o, m, k, k2) {
+    if (k2 === undefined) k2 = k;
+    Object.defineProperty(o, k2, { enumerable: true, get: function() { return m[k]; } });
+}) : (function(o, m, k, k2) {
+    if (k2 === undefined) k2 = k;
+    o[k2] = m[k];
+}));
+var __setModuleDefault = (this && this.__setModuleDefault) || (Object.create ? (function(o, v) {
+    Object.defineProperty(o, "default", { enumerable: true, value: v });
+}) : function(o, v) {
+    o["default"] = v;
+});
+var __importStar = (this && this.__importStar) || function (mod) {
+    if (mod && mod.__esModule) return mod;
+    var result = {};
+    if (mod != null) for (var k in mod) if (k !== "default" && Object.prototype.hasOwnProperty.call(mod, k)) __createBinding(result, mod, k);
+    __setModuleDefault(result, mod);
+    return result;
+};
+define(["require", "exports", "./0"], function (require, exports, _0_1) {
+    "use strict";
+    exports.__esModule = true;
+    exports["default"] = void 0;
+    exports["default"] = __importStar(_0_1);
+});
+//// [11.js]
+var __createBinding = (this && this.__createBinding) || (Object.create ? (function(o, m, k, k2) {
+    if (k2 === undefined) k2 = k;
+    Object.defineProperty(o, k2, { enumerable: true, get: function() { return m[k]; } });
+}) : (function(o, m, k, k2) {
+    if (k2 === undefined) k2 = k;
+    o[k2] = m[k];
+}));
+var __setModuleDefault = (this && this.__setModuleDefault) || (Object.create ? (function(o, v) {
+    Object.defineProperty(o, "default", { enumerable: true, value: v });
+}) : function(o, v) {
+    o["default"] = v;
+});
+var __importStar = (this && this.__importStar) || function (mod) {
+    if (mod && mod.__esModule) return mod;
+    var result = {};
+    if (mod != null) for (var k in mod) if (k !== "default" && Object.prototype.hasOwnProperty.call(mod, k)) __createBinding(result, mod, k);
+    __setModuleDefault(result, mod);
+    return result;
+};
+define(["require", "exports", "./0"], function (require, exports, ns) {
+    "use strict";
+    exports.__esModule = true;
+    ns = __importStar(ns);
+    exports["default"] = ns;
+});
+//// [2.js]
+var __importDefault = (this && this.__importDefault) || function (mod) {
+    return (mod && mod.__esModule) ? mod : { "default": mod };
+};
+define(["require", "exports", "./1", "./11"], function (require, exports, _1_1, _11_1) {
+    "use strict";
+    exports.__esModule = true;
+    _1_1 = __importDefault(_1_1);
+    _11_1 = __importDefault(_11_1);
+    _1_1["default"].a;
+    _11_1["default"].a;
+    _1_1["default"].b;
+    _11_1["default"].b;
+});
+
+
+//// [0.d.ts]
+export declare const a = 1;
+export declare const b = 2;
+//// [1.d.ts]
+export * as default from './0';
+//// [11.d.ts]
+import * as ns from './0';
+export default ns;
+//// [2.d.ts]
+export {};
diff --git a/tests/baselines/reference/exportAsNamespace4(module=amd).symbols b/tests/baselines/reference/exportAsNamespace4(module=amd).symbols
@@ -0,0 +1,45 @@
+=== tests/cases/conformance/es2020/modules/0.ts ===
+export const a = 1;
+>a : Symbol(a, Decl(0.ts, 0, 12))
+
+export const b = 2;
+>b : Symbol(b, Decl(0.ts, 1, 12))
+
+=== tests/cases/conformance/es2020/modules/1.ts ===
+export * as default from './0';
+>default : Symbol(default, Decl(1.ts, 0, 6))
+
+=== tests/cases/conformance/es2020/modules/11.ts ===
+import * as ns from './0';
+>ns : Symbol(ns, Decl(11.ts, 0, 6))
+
+export default ns;
+>ns : Symbol(ns, Decl(11.ts, 0, 6))
+
+=== tests/cases/conformance/es2020/modules/2.ts ===
+import foo from './1'
+>foo : Symbol(foo, Decl(2.ts, 0, 6))
+
+import foo1 from './11'
+>foo1 : Symbol(foo1, Decl(2.ts, 1, 6))
+
+foo.a;
+>foo.a : Symbol(foo.a, Decl(0.ts, 0, 12))
+>foo : Symbol(foo, Decl(2.ts, 0, 6))
+>a : Symbol(foo.a, Decl(0.ts, 0, 12))
+
+foo1.a;
+>foo1.a : Symbol(foo.a, Decl(0.ts, 0, 12))
+>foo1 : Symbol(foo1, Decl(2.ts, 1, 6))
+>a : Symbol(foo.a, Decl(0.ts, 0, 12))
+
+foo.b;
+>foo.b : Symbol(foo.b, Decl(0.ts, 1, 12))
+>foo : Symbol(foo, Decl(2.ts, 0, 6))
+>b : Symbol(foo.b, Decl(0.ts, 1, 12))
+
+foo1.b;
+>foo1.b : Symbol(foo.b, Decl(0.ts, 1, 12))
+>foo1 : Symbol(foo1, Decl(2.ts, 1, 6))
+>b : Symbol(foo.b, Decl(0.ts, 1, 12))
+
diff --git a/tests/baselines/reference/exportAsNamespace4(module=amd).types b/tests/baselines/reference/exportAsNamespace4(module=amd).types
@@ -0,0 +1,47 @@
+=== tests/cases/conformance/es2020/modules/0.ts ===
+export const a = 1;
+>a : 1
+>1 : 1
+
+export const b = 2;
+>b : 2
+>2 : 2
+
+=== tests/cases/conformance/es2020/modules/1.ts ===
+export * as default from './0';
+>default : typeof import("tests/cases/conformance/es2020/modules/0")
+
+=== tests/cases/conformance/es2020/modules/11.ts ===
+import * as ns from './0';
+>ns : typeof ns
+
+export default ns;
+>ns : typeof ns
+
+=== tests/cases/conformance/es2020/modules/2.ts ===
+import foo from './1'
+>foo : typeof foo
+
+import foo1 from './11'
+>foo1 : typeof foo
+
+foo.a;
+>foo.a : 1
+>foo : typeof foo
+>a : 1
+
+foo1.a;
+>foo1.a : 1
+>foo1 : typeof foo
+>a : 1
+
+foo.b;
+>foo.b : 2
+>foo : typeof foo
+>b : 2
+
+foo1.b;
+>foo1.b : 2
+>foo1 : typeof foo
+>b : 2
+
diff --git a/tests/baselines/reference/exportAsNamespace4(module=commonjs).js b/tests/baselines/reference/exportAsNamespace4(module=commonjs).js
@@ -0,0 +1,101 @@
+//// [tests/cases/conformance/es2020/modules/exportAsNamespace4.ts] ////
+
+//// [0.ts]
+export const a = 1;
+export const b = 2;
+
+//// [1.ts]
+export * as default from './0';
+
+//// [11.ts]
+import * as ns from './0';
+export default ns;
+
+//// [2.ts]
+import foo from './1'
+import foo1 from './11'
+
+foo.a;
+foo1.a;
+
+foo.b;
+foo1.b;
+
+//// [0.js]
+"use strict";
+exports.__esModule = true;
+exports.b = exports.a = void 0;
+exports.a = 1;
+exports.b = 2;
+//// [1.js]
+"use strict";
+var __createBinding = (this && this.__createBinding) || (Object.create ? (function(o, m, k, k2) {
+    if (k2 === undefined) k2 = k;
+    Object.defineProperty(o, k2, { enumerable: true, get: function() { return m[k]; } });
+}) : (function(o, m, k, k2) {
+    if (k2 === undefined) k2 = k;
+    o[k2] = m[k];
+}));
+var __setModuleDefault = (this && this.__setModuleDefault) || (Object.create ? (function(o, v) {
+    Object.defineProperty(o, "default", { enumerable: true, value: v });
+}) : function(o, v) {
+    o["default"] = v;
+});
+var __importStar = (this && this.__importStar) || function (mod) {
+    if (mod && mod.__esModule) return mod;
+    var result = {};
+    if (mod != null) for (var k in mod) if (k !== "default" && Object.prototype.hasOwnProperty.call(mod, k)) __createBinding(result, mod, k);
+    __setModuleDefault(result, mod);
+    return result;
+};
+exports.__esModule = true;
+exports["default"] = void 0;
+exports["default"] = __importStar(require("./0"));
+//// [11.js]
+"use strict";
+var __createBinding = (this && this.__createBinding) || (Object.create ? (function(o, m, k, k2) {
+    if (k2 === undefined) k2 = k;
+    Object.defineProperty(o, k2, { enumerable: true, get: function() { return m[k]; } });
+}) : (function(o, m, k, k2) {
+    if (k2 === undefined) k2 = k;
+    o[k2] = m[k];
+}));
+var __setModuleDefault = (this && this.__setModuleDefault) || (Object.create ? (function(o, v) {
+    Object.defineProperty(o, "default", { enumerable: true, value: v });
+}) : function(o, v) {
+    o["default"] = v;
+});
+var __importStar = (this && this.__importStar) || function (mod) {
+    if (mod && mod.__esModule) return mod;
+    var result = {};
+    if (mod != null) for (var k in mod) if (k !== "default" && Object.prototype.hasOwnProperty.call(mod, k)) __createBinding(result, mod, k);
+    __setModuleDefault(result, mod);
+    return result;
+};
+exports.__esModule = true;
+var ns = __importStar(require("./0"));
+exports["default"] = ns;
+//// [2.js]
+"use strict";
+var __importDefault = (this && this.__importDefault) || function (mod) {
+    return (mod && mod.__esModule) ? mod : { "default": mod };
+};
+exports.__esModule = true;
+var _1_1 = __importDefault(require("./1"));
+var _11_1 = __importDefault(require("./11"));
+_1_1["default"].a;
+_11_1["default"].a;
+_1_1["default"].b;
+_11_1["default"].b;
+
+
+//// [0.d.ts]
+export declare const a = 1;
+export declare const b = 2;
+//// [1.d.ts]
+export * as default from './0';
+//// [11.d.ts]
+import * as ns from './0';
+export default ns;
+//// [2.d.ts]
+export {};