Hoist function exports to top of module body in CJS/AMD/UMD

src/compiler/transformers/module/module.ts

@@ -264,21 +264,26 @@ export function transformModule(context: TransformationContext): (x: SourceFile
         if (shouldEmitUnderscoreUnderscoreESModule()) {
             append(statements, createUnderscoreUnderscoreESModule());
         }
-        if (length(currentModuleInfo.exportedNames)) {
+        if (some(currentModuleInfo.exportedNames)) {
             const chunkSize = 50;
-            for (let i = 0; i < currentModuleInfo.exportedNames!.length; i += chunkSize) {
+            for (let i = 0; i < currentModuleInfo.exportedNames.length; i += chunkSize) {
                 append(
                     statements,
                     factory.createExpressionStatement(
                         reduceLeft(
-                            currentModuleInfo.exportedNames!.slice(i, i + chunkSize),
+                            currentModuleInfo.exportedNames.slice(i, i + chunkSize),
                             (prev, nextId) => factory.createAssignment(factory.createPropertyAccessExpression(factory.createIdentifier("exports"), factory.createIdentifier(idText(nextId))), prev),
                             factory.createVoidZero() as Expression,
                         ),
                     ),
                 );
             }
         }
+        if (some(currentModuleInfo.exportedFunctions)) {
+            for (const f of currentModuleInfo.exportedFunctions) {
+                appendExportsOfHoistedDeclaration(statements, f);
+            }
+        }
 
         append(statements, visitNode(currentModuleInfo.externalHelpersImportDeclaration, topLevelVisitor, isStatement));
         addRange(statements, visitNodes(node.statements, topLevelVisitor, isStatement, statementOffset));
@@ -601,9 +606,14 @@ export function transformModule(context: TransformationContext): (x: SourceFile
         if (shouldEmitUnderscoreUnderscoreESModule()) {
             append(statements, createUnderscoreUnderscoreESModule());
         }
-        if (length(currentModuleInfo.exportedNames)) {
+        if (some(currentModuleInfo.exportedNames)) {
             append(statements, factory.createExpressionStatement(reduceLeft(currentModuleInfo.exportedNames, (prev, nextId) => factory.createAssignment(factory.createPropertyAccessExpression(factory.createIdentifier("exports"), factory.createIdentifier(idText(nextId))), prev), factory.createVoidZero() as Expression)));
         }
+        if (some(currentModuleInfo.exportedFunctions)) {
+            for (const f of currentModuleInfo.exportedFunctions) {
+                appendExportsOfHoistedDeclaration(statements, f);
+            }
+        }
 
         // Visit each statement of the module body.
         append(statements, visitNode(currentModuleInfo.externalHelpersImportDeclaration, topLevelVisitor, isStatement));
@@ -1704,7 +1714,7 @@ export function transformModule(context: TransformationContext): (x: SourceFile
             statements = append(statements, visitEachChild(node, visitor, context));
         }
 
-        statements = appendExportsOfHoistedDeclaration(statements, node);
+        // NOTE: CommonJS/AMD/UMD exports are hoisted to the top of the module body and do not need to be added here.
         return singleOrMany(statements);
     }
 

src/compiler/transformers/module/system.ts

@@ -433,7 +433,7 @@ export function transformSystemModule(context: TransformationContext): (x: Sourc
         // this set is used to filter names brought by star expors.
 
         // local names set should only be added if we have anything exported
-        if (!moduleInfo.exportedNames && moduleInfo.exportSpecifiers.size === 0) {
+        if (!some(moduleInfo.exportedNames) && !some(moduleInfo.exportedFunctions) && moduleInfo.exportSpecifiers.size === 0) {
             // no exported declarations (export var ...) or export specifiers (export {x})
             // check if we have any non star export declarations.
             let hasExportDeclarationWithExportClause = false;
@@ -469,6 +469,23 @@ export function transformSystemModule(context: TransformationContext): (x: Sourc
             }
         }
 
+        if (moduleInfo.exportedFunctions) {
+            for (const f of moduleInfo.exportedFunctions) {
+                if (hasSyntacticModifier(f, ModifierFlags.Default)) {
+                    continue;
+                }
+                Debug.assert(!!f.name);
+
+                // write name of exported declaration, i.e 'export var x...'
+                exportedNames.push(
+                    factory.createPropertyAssignment(
+                        factory.createStringLiteralFromNode(f.name),
+                        factory.createTrue(),
+                    ),
+                );
+            }
+        }
+
         const exportedNamesStorageRef = factory.createUniqueName("exportedNames");
         statements.push(
             factory.createVariableStatement(

src/compiler/transformers/utilities.ts

@@ -103,7 +103,8 @@ export interface ExternalModuleInfo {
     externalHelpersImportDeclaration: ImportDeclaration | undefined; // import of external helpers
     exportSpecifiers: IdentifierNameMap<ExportSpecifier[]>; // file-local export specifiers by name (no reexports)
     exportedBindings: Identifier[][]; // exported names of local declarations
-    exportedNames: Identifier[] | undefined; // all exported names in the module, both local and reexported
+    exportedNames: Identifier[] | undefined; // all exported names in the module, both local and reexported, excluding the names of locally exported function declarations
+    exportedFunctions: FunctionDeclaration[] | undefined; // all of the top-level exported function declarations
     exportEquals: ExportAssignment | undefined; // an export= declaration if one was present
     hasExportStarsToExportValues: boolean; // whether this module contains export*
 }
@@ -171,6 +172,7 @@ export function collectExternalModuleInfo(context: TransformationContext, source
     const exportedBindings: Identifier[][] = [];
     const uniqueExports = new Map<string, boolean>();
     let exportedNames: Identifier[] | undefined;
+    let exportedFunctions: FunctionDeclaration[] | undefined;
     let hasExportDefault = false;
     let exportEquals: ExportAssignment | undefined;
     let hasExportStarsToExportValues = false;
@@ -250,6 +252,7 @@ export function collectExternalModuleInfo(context: TransformationContext, source
 
             case SyntaxKind.FunctionDeclaration:
                 if (hasSyntacticModifier(node, ModifierFlags.Export)) {
+                    exportedFunctions = append(exportedFunctions, node as FunctionDeclaration);
                     if (hasSyntacticModifier(node, ModifierFlags.Default)) {
                         // export default function() { }
                         if (!hasExportDefault) {
@@ -263,7 +266,6 @@ export function collectExternalModuleInfo(context: TransformationContext, source
                         if (!uniqueExports.get(idText(name))) {
                             multiMapSparseArrayAdd(exportedBindings, getOriginalNodeId(node), name);
                             uniqueExports.set(idText(name), true);
-                            exportedNames = append(exportedNames, name);
                         }
                     }
                 }
@@ -297,7 +299,7 @@ export function collectExternalModuleInfo(context: TransformationContext, source
         externalImports.unshift(externalHelpersImportDeclaration);
     }
 
-    return { externalImports, exportSpecifiers, exportEquals, hasExportStarsToExportValues, exportedBindings, exportedNames, externalHelpersImportDeclaration };
+    return { externalImports, exportSpecifiers, exportEquals, hasExportStarsToExportValues, exportedBindings, exportedNames, exportedFunctions, externalHelpersImportDeclaration };
 
     function addExportedNamesForExportDeclaration(node: ExportDeclaration) {
         for (const specifier of cast(node.exportClause, isNamedExports).elements) {

tests/baselines/reference/APISample_compile.js

@@ -54,7 +54,7 @@ compile(process.argv.slice(2), {
  *       Please log a "breaking change" issue for any API breaking change affecting this issue
  */
 Object.defineProperty(exports, "__esModule", { value: true });
-exports.compile = void 0;
+exports.compile = compile;
 var ts = require("typescript");
 function compile(fileNames, options) {
     var program = ts.createProgram(fileNames, options);
@@ -73,7 +73,6 @@ function compile(fileNames, options) {
     console.log("Process exiting with code '".concat(exitCode, "'."));
     process.exit(exitCode);
 }
-exports.compile = compile;
 compile(process.argv.slice(2), {
     noEmitOnError: true, noImplicitAny: true,
     target: ts.ScriptTarget.ES5, module: ts.ModuleKind.CommonJS

tests/baselines/reference/APISample_linter.js

@@ -80,7 +80,7 @@ fileNames.forEach(fileName => {
  *       Please log a "breaking change" issue for any API breaking change affecting this issue
  */
 Object.defineProperty(exports, "__esModule", { value: true });
-exports.delint = void 0;
+exports.delint = delint;
 var ts = require("typescript");
 function delint(sourceFile) {
     delintNode(sourceFile);
@@ -119,7 +119,6 @@ function delint(sourceFile) {
         console.log("".concat(sourceFile.fileName, " (").concat(line + 1, ",").concat(character + 1, "): ").concat(message));
     }
 }
-exports.delint = delint;
 var fileNames = process.argv.slice(2);
 fileNames.forEach(function (fileName) {
     // Parse a file

tests/baselines/reference/APISample_parseConfig.js

@@ -52,7 +52,7 @@ export function createProgram(rootFiles: string[], compilerOptionsJson: string):
  *       Please log a "breaking change" issue for any API breaking change affecting this issue
  */
 Object.defineProperty(exports, "__esModule", { value: true });
-exports.createProgram = void 0;
+exports.createProgram = createProgram;
 var ts = require("typescript");
 function printError(error) {
     if (!error) {
@@ -77,4 +77,3 @@ function createProgram(rootFiles, compilerOptionsJson) {
     }
     return ts.createProgram(rootFiles, settings.options);
 }
-exports.createProgram = createProgram;

tests/baselines/reference/aliasUsedAsNameValue.js

@@ -25,9 +25,8 @@ exports.id = void 0;
 //// [aliasUsedAsNameValue_1.js]
 "use strict";
 Object.defineProperty(exports, "__esModule", { value: true });
-exports.b = void 0;
-function b(a) { return null; }
 exports.b = b;
+function b(a) { return null; }
 //// [aliasUsedAsNameValue_2.js]
 "use strict";
 Object.defineProperty(exports, "__esModule", { value: true });

tests/baselines/reference/amdDeclarationEmitNoExtraDeclare.js

@@ -40,7 +40,7 @@ var __extends = (this && this.__extends) || (function () {
 define("Configurable", ["require", "exports"], function (require, exports) {
     "use strict";
     Object.defineProperty(exports, "__esModule", { value: true });
-    exports.Configurable = void 0;
+    exports.Configurable = Configurable;
     function Configurable(base) {
         return /** @class */ (function (_super) {
             __extends(class_1, _super);
@@ -54,7 +54,6 @@ define("Configurable", ["require", "exports"], function (require, exports) {
             return class_1;
         }(base));
     }
-    exports.Configurable = Configurable;
 });
 define("Class", ["require", "exports", "Configurable"], function (require, exports, Configurable_1) {
     "use strict";

tests/baselines/reference/anonClassDeclarationEmitIsAnon.js

@@ -52,7 +52,8 @@ var __extends = (this && this.__extends) || (function () {
     };
 })();
 Object.defineProperty(exports, "__esModule", { value: true });
-exports.Timestamped = exports.wrapClass = void 0;
+exports.wrapClass = wrapClass;
+exports.Timestamped = Timestamped;
 function wrapClass(param) {
     return /** @class */ (function () {
         function Wrapped() {
@@ -63,7 +64,6 @@ function wrapClass(param) {
         return Wrapped;
     }());
 }
-exports.wrapClass = wrapClass;
 function Timestamped(Base) {
     return /** @class */ (function (_super) {
         __extends(class_1, _super);
@@ -75,7 +75,6 @@ function Timestamped(Base) {
         return class_1;
     }(Base));
 }
-exports.Timestamped = Timestamped;
 //// [index.js]
 "use strict";
 var __extends = (this && this.__extends) || (function () {

tests/baselines/reference/anonymousClassDeclarationDoesntPrintWithReadonly.js

@@ -27,7 +27,8 @@ var __extends = (this && this.__extends) || (function () {
     };
 })();
 Object.defineProperty(exports, "__esModule", { value: true });
-exports.y = exports.X = void 0;
+exports.X = void 0;
+exports.y = y;
 var X = /** @class */ (function () {
     function X(a) {
         this.a = a;
@@ -44,7 +45,6 @@ function y() {
         return class_1;
     }(X));
 }
-exports.y = y;
 
 
 //// [anonymousClassDeclarationDoesntPrintWithReadonly.d.ts]

tests/baselines/reference/anonymousDefaultExportsAmd.js

@@ -18,6 +18,6 @@ define(["require", "exports"], function (require, exports) {
 define(["require", "exports"], function (require, exports) {
     "use strict";
     Object.defineProperty(exports, "__esModule", { value: true });
-    function default_1() { }
     exports.default = default_1;
+    function default_1() { }
 });

tests/baselines/reference/anonymousDefaultExportsCommonjs.js

@@ -15,5 +15,5 @@ exports.default = default_1;
 //// [b.js]
 "use strict";
 Object.defineProperty(exports, "__esModule", { value: true });
-function default_1() { }
 exports.default = default_1;
+function default_1() { }

tests/baselines/reference/anonymousDefaultExportsUmd.js

@@ -34,6 +34,6 @@ export default function() {}
 })(function (require, exports) {
     "use strict";
     Object.defineProperty(exports, "__esModule", { value: true });
-    function default_1() { }
     exports.default = default_1;
+    function default_1() { }
 });

tests/baselines/reference/arrayDestructuringInSwitch1.js

@@ -26,7 +26,7 @@ export function evaluate(expression: Expression): boolean {
 //// [arrayDestructuringInSwitch1.js]
 "use strict";
 Object.defineProperty(exports, "__esModule", { value: true });
-exports.evaluate = void 0;
+exports.evaluate = evaluate;
 function evaluate(expression) {
     if (Array.isArray(expression)) {
         var operator = expression[0], operands = expression.slice(1);
@@ -46,4 +46,3 @@ function evaluate(expression) {
         return expression === 'true';
     }
 }
-exports.evaluate = evaluate;

tests/baselines/reference/asOperator4.js

@@ -14,9 +14,8 @@ import { foo } from './foo';
 //// [foo.js]
 "use strict";
 Object.defineProperty(exports, "__esModule", { value: true });
-exports.foo = void 0;
-function foo() { }
 exports.foo = foo;
+function foo() { }
 //// [bar.js]
 "use strict";
 Object.defineProperty(exports, "__esModule", { value: true });

tests/baselines/reference/assertionFunctionWildcardImport2.js

@@ -29,7 +29,6 @@ function isNonNullable(obj) {
         throw new Error("Must not be a nullable value");
     }
 }
-exports.isNonNullable = isNonNullable;
 //// [test.js]
 "use strict";
 Object.defineProperty(exports, "__esModule", { value: true });

tests/baselines/reference/baseConstraintOfDecorator.js

@@ -39,7 +39,8 @@ var __extends = (this && this.__extends) || (function () {
     };
 })();
 Object.defineProperty(exports, "__esModule", { value: true });
-exports.classExtender2 = exports.classExtender = void 0;
+exports.classExtender = classExtender;
+exports.classExtender2 = classExtender2;
 function classExtender(superClass, _instanceModifier) {
     return /** @class */ (function (_super) {
         __extends(decoratorFunc, _super);
@@ -55,7 +56,6 @@ function classExtender(superClass, _instanceModifier) {
         return decoratorFunc;
     }(superClass));
 }
-exports.classExtender = classExtender;
 var MyClass = /** @class */ (function () {
     function MyClass() {
     }
@@ -76,4 +76,3 @@ function classExtender2(superClass, _instanceModifier) {
         return decoratorFunc;
     }(superClass));
 }
-exports.classExtender2 = classExtender2;

tests/baselines/reference/checkJsxUnionSFXContextualTypeInferredCorrectly.js

@@ -47,17 +47,16 @@ var __importDefault = (this && this.__importDefault) || function (mod) {
     return (mod && mod.__esModule) ? mod : { "default": mod };
 };
 Object.defineProperty(exports, "__esModule", { value: true });
-exports.HereIsTheError = exports.ComponentWithUnion = void 0;
+exports.ComponentWithUnion = ComponentWithUnion;
+exports.HereIsTheError = HereIsTheError;
 var react_1 = __importDefault(require("react"));
 function ComponentWithUnion(props) {
     return react_1.default.createElement("h1", null);
 }
-exports.ComponentWithUnion = ComponentWithUnion;
 // Usage with React tsx
 function HereIsTheError() {
     return (react_1.default.createElement(ComponentWithUnion, { multi: false, value: 's', onChange: function (val) { return console.log(val); } }));
 }
-exports.HereIsTheError = HereIsTheError;
 // Usage with pure TypeScript
 ComponentWithUnion({
     multi: false,

tests/baselines/reference/circularReferenceInImport.js

@@ -17,11 +17,10 @@ export function foo() {
 //// [app.js]
 "use strict";
 Object.defineProperty(exports, "__esModule", { value: true });
-exports.foo = void 0;
+exports.foo = foo;
 function foo() {
     return new Object();
 }
-exports.foo = foo;
 
 
 //// [app.d.ts]

tests/baselines/reference/circularResolvedSignature.js

@@ -21,12 +21,11 @@ export function Component() {
 //// [circularResolvedSignature.js]
 "use strict";
 Object.defineProperty(exports, "__esModule", { value: true });
-exports.Component = void 0;
+exports.Component = Component;
 function Component() {
     var _a = useState(function () { return ({
         value: "string", // this should be a number
         foo: function (arg) { return setState(arg); },
         bar: function (arg) { return setState(arg); },
     }); }), state = _a[0], setState = _a[1];
 }
-exports.Component = Component;