Add toStringTag to dynamic entries and interop helpers

src/Chunk.ts

@@ -707,6 +707,12 @@ export default class Chunk {
 			});
 		}
 
+		// console.log(this.facadeModule?.id);
+		if (this.outputOptions.preserveModules) {
+			if (this.facadeModule === null) {
+				throw new Error(String(this.facadeModule === null));
+			}
+		}
 		const magicString = finalise(
 			this.renderedSource!,
 			{
@@ -716,9 +722,10 @@ export default class Chunk {
 				hasExports,
 				indentString: this.indentString,
 				intro: addons.intro!,
-				isEntryModuleFacade:
+				isEntryFacade:
 					this.outputOptions.preserveModules ||
 					(this.facadeModule !== null && this.facadeModule.info.isEntry),
+				isModuleFacade: this.facadeModule !== null,
 				namedExportsMode: this.exportMode !== 'default',
 				outro: addons.outro!,
 				usesTopLevelAwait,

src/finalisers/amd.ts

@@ -24,7 +24,8 @@ export default function amd(
 		hasExports,
 		indentString: t,
 		intro,
-		isEntryModuleFacade,
+		isEntryFacade,
+		isModuleFacade,
 		namedExportsMode,
 		outro,
 		varOrConst,
@@ -74,6 +75,7 @@ export default function amd(
 			interop,
 			externalLiveBindings,
 			freeze,
+			namespaceToStringTag,
 			accessedGlobals,
 			_,
 			n,
@@ -91,14 +93,17 @@ export default function amd(
 		t,
 		externalLiveBindings
 	);
-	magicString.append(
-		`${exportBlock}${
-			namedExportsMode && hasExports && isEntryModuleFacade && esModule
-				? `${n}${n}${getNamespaceMarkers(namespaceToStringTag, _, n)}`
-				: ''
-		}${outro}`
+	let namespaceMarkers = getNamespaceMarkers(
+		namedExportsMode && hasExports,
+		isEntryFacade && esModule,
+		isModuleFacade && namespaceToStringTag,
+		_,
+		n
 	);
-
+	if (namespaceMarkers) {
+		namespaceMarkers = n + n + namespaceMarkers;
+	}
+	magicString.append(`${exportBlock}${namespaceMarkers}${outro}`);
 	return magicString
 		.indent(t)
 		.prepend(`${amdDefine}(${params}function${_}(${args.join(`,${_}`)})${_}{${useStrict}${n}${n}`)

src/finalisers/cjs.ts

@@ -14,7 +14,8 @@ export default function cjs(
 		hasExports,
 		indentString: t,
 		intro,
-		isEntryModuleFacade,
+		isEntryFacade,
+		isModuleFacade,
 		namedExportsMode,
 		outro,
 		varOrConst
@@ -34,17 +35,24 @@ export default function cjs(
 	const _ = compact ? '' : ' ';
 
 	const useStrict = strict ? `'use strict';${n}${n}` : '';
-	const namespaceMarkers =
-		namedExportsMode && hasExports && isEntryModuleFacade && esModule
-			? `${getNamespaceMarkers(namespaceToStringTag, _, n)}${n}${n}`
-			: '';
+	let namespaceMarkers = getNamespaceMarkers(
+		namedExportsMode && hasExports,
+		isEntryFacade && esModule,
+		isModuleFacade && namespaceToStringTag,
+		_,
+		n
+	);
+	if (namespaceMarkers) {
+		namespaceMarkers += n + n;
+	}
 	const importBlock = getImportBlock(dependencies, compact, varOrConst, n, _);
 	const interopBlock = getInteropBlock(
 		dependencies,
 		varOrConst,
 		interop,
 		externalLiveBindings,
 		freeze,
+		namespaceToStringTag,
 		accessedGlobals,
 		_,
 		n,

src/finalisers/iife.ts

@@ -83,6 +83,7 @@ export default function iife(
 		interop,
 		externalLiveBindings,
 		freeze,
+		namespaceToStringTag,
 		accessedGlobals,
 		_,
 		n,
@@ -117,12 +118,16 @@ export default function iife(
 		t,
 		externalLiveBindings
 	);
-	magicString.append(
-		`${exportBlock}${
-			namedExportsMode && hasExports && esModule
-				? `${n}${n}${getNamespaceMarkers(namespaceToStringTag, _, n)}`
-				: ''
-		}${outro}`
+	let namespaceMarkers = getNamespaceMarkers(
+		namedExportsMode && hasExports,
+		esModule,
+		namespaceToStringTag,
+		_,
+		n
 	);
+	if (namespaceMarkers) {
+		namespaceMarkers = n + n + namespaceMarkers;
+	}
+	magicString.append(`${exportBlock}${namespaceMarkers}${outro}`);
 	return magicString.indent(t).prepend(wrapperIntro).append(wrapperOutro);
 }

src/finalisers/index.ts

@@ -15,7 +15,8 @@ export interface FinaliserOptions {
 	hasExports: boolean;
 	indentString: string;
 	intro: string;
-	isEntryModuleFacade: boolean;
+	isEntryFacade: boolean;
+	isModuleFacade: boolean;
 	namedExportsMode: boolean;
 	outro: string;
 	usesTopLevelAwait: boolean;

src/finalisers/shared/getExportBlock.ts

@@ -175,8 +175,32 @@ function getReexportedImportName(
 	return `${moduleVariableName}.${imported}`;
 }
 
-export function getNamespaceMarkers(namespaceToStringTag: boolean, _: string, n: string): string {
-	return `Object.defineProperty(exports,${_}'__esModule',${_}{${_}value:${_}true${_}});${
-		namespaceToStringTag ? `${n}exports[Symbol.toStringTag]${_}=${_}'Module';` : ''
-	}`;
+function getEsModuleExport(_: string): string {
+	return `Object.defineProperty(exports,${_}'__esModule',${_}{${_}value:${_}true${_}});`;
+}
+
+function getNamespaceToStringExport(_: string): string {
+	return `exports[Symbol.toStringTag]${_}=${_}'Module';`;
+}
+
+export function getNamespaceMarkers(
+	hasNamedExports: boolean,
+	addEsModule: boolean,
+	addNamespaceToStringTag: boolean,
+	_: string,
+	n: string
+): string {
+	let namespaceMarkers = '';
+	if (hasNamedExports) {
+		if (addEsModule) {
+			namespaceMarkers += getEsModuleExport(_);
+		}
+		if (addNamespaceToStringTag) {
+			if (namespaceMarkers) {
+				namespaceMarkers += n;
+			}
+			namespaceMarkers += getNamespaceToStringExport(_);
+		}
+	}
+	return namespaceMarkers;
 }

src/finalisers/shared/getInteropBlock.ts

@@ -13,6 +13,7 @@ export default function getInteropBlock(
 	interop: GetInterop,
 	externalLiveBindings: boolean,
 	freeze: boolean,
+	namespaceToStringTag: boolean,
 	accessedGlobals: Set<string>,
 	_: string,
 	n: string,
@@ -92,6 +93,7 @@ export default function getInteropBlock(
 		s,
 		t,
 		externalLiveBindings,
-		freeze
+		freeze,
+		namespaceToStringTag
 	)}${interopStatements.length > 0 ? `${interopStatements.join(n)}${n}${n}` : ''}`;
 }

src/finalisers/umd.ts

@@ -161,6 +161,7 @@ export default function umd(
 			interop,
 			externalLiveBindings,
 			freeze,
+			namespaceToStringTag,
 			accessedGlobals,
 			_,
 			n,
@@ -178,13 +179,16 @@ export default function umd(
 		t,
 		externalLiveBindings
 	);
-	magicString.append(
-		`${exportBlock}${
-			namedExportsMode && hasExports && esModule
-				? `${n}${n}${getNamespaceMarkers(namespaceToStringTag, _, n)}`
-				: ''
-		}${outro}`
+	let namespaceMarkers = getNamespaceMarkers(
+		namedExportsMode && hasExports,
+		esModule,
+		namespaceToStringTag,
+		_,
+		n
 	);
-
+	if (namespaceMarkers) {
+		namespaceMarkers = n + n + namespaceMarkers;
+	}
+	magicString.append(`${exportBlock}${namespaceMarkers}${outro}`);
 	return magicString.trim().indent(t).append(wrapperOutro).prepend(wrapperIntro);
 }

src/utils/interopHelpers.ts

@@ -48,11 +48,21 @@ export function getHelpersBlock(
 	s: string,
 	t: string,
 	liveBindings: boolean,
-	freeze: boolean
+	freeze: boolean,
+	namespaceToStringTag: boolean
 ): string {
 	return HELPER_NAMES.map(variable =>
 		usedHelpers.has(variable) || accessedGlobals.has(variable)
-			? HELPER_GENERATORS[variable](_, n, s, t, liveBindings, freeze, usedHelpers)
+			? HELPER_GENERATORS[variable](
+					_,
+					n,
+					s,
+					t,
+					liveBindings,
+					freeze,
+					namespaceToStringTag,
+					usedHelpers
+			  )
 			: ''
 	).join('');
 }
@@ -65,6 +75,7 @@ const HELPER_GENERATORS: {
 		t: string,
 		liveBindings: boolean,
 		freeze: boolean,
+		namespaceToStringTag: boolean,
 		usedHelpers: Set<string>
 	) => string;
 } = {
@@ -76,27 +87,42 @@ const HELPER_GENERATORS: {
 		`function ${INTEROP_DEFAULT_LEGACY_VARIABLE}${_}(e)${_}{${_}return ` +
 		`e${_}&&${_}typeof e${_}===${_}'object'${_}&&${_}'default'${_}in e${_}?${_}` +
 		`${liveBindings ? getDefaultLiveBinding(_) : getDefaultStatic(_)}${s}${_}}${n}${n}`,
-	[INTEROP_NAMESPACE_VARIABLE]: (_, n, s, t, liveBindings, freeze, usedHelpers) =>
+	[INTEROP_NAMESPACE_VARIABLE]: (
+		_,
+		n,
+		s,
+		t,
+		liveBindings,
+		freeze,
+		namespaceToStringTag,
+		usedHelpers
+	) =>
 		`function ${INTEROP_NAMESPACE_VARIABLE}(e)${_}{${n}` +
 		(usedHelpers.has(INTEROP_NAMESPACE_DEFAULT_VARIABLE)
 			? `${t}return e${_}&&${_}e.__esModule${_}?${_}e${_}:${_}${INTEROP_NAMESPACE_DEFAULT_VARIABLE}(e)${s}${n}`
 			: `${t}if${_}(e${_}&&${_}e.__esModule)${_}return e;${n}` +
-			  createNamespaceObject(_, n, t, t, liveBindings, freeze)) +
+			  createNamespaceObject(_, n, t, t, liveBindings, freeze, namespaceToStringTag)) +
 		`}${n}${n}`,
-	[INTEROP_NAMESPACE_DEFAULT_VARIABLE]: (_, n, _s, t, liveBindings, freeze) =>
+	[INTEROP_NAMESPACE_DEFAULT_VARIABLE]: (_, n, _s, t, liveBindings, freeze, namespaceToStringTag) =>
 		`function ${INTEROP_NAMESPACE_DEFAULT_VARIABLE}(e)${_}{${n}` +
-		createNamespaceObject(_, n, t, t, liveBindings, freeze) +
+		createNamespaceObject(_, n, t, t, liveBindings, freeze, namespaceToStringTag) +
 		`}${n}${n}`,
 	[INTEROP_NAMESPACE_DEFAULT_ONLY_VARIABLE]: (
 		_: string,
 		n: string,
 		_s: string,
 		t: string,
 		_liveBindings: boolean,
-		freeze: boolean
+		freeze: boolean,
+		namespaceToStringTag: boolean
 	) =>
 		`function ${INTEROP_NAMESPACE_DEFAULT_ONLY_VARIABLE}(e)${_}{${n}` +
-		`${t}return ${getFrozen(`{__proto__: null,${_}'default':${_}e}`, freeze)};${n}` +
+		`${t}return ${getFrozen(
+			`{__proto__: null,${
+				namespaceToStringTag ? `${_}[Symbol.toStringTag]:${_}'Module',` : ''
+			}${_}'default':${_}e}`,
+			freeze
+		)};${n}` +
 		`}${n}${n}`
 };
 
@@ -114,10 +140,15 @@ function createNamespaceObject(
 	t: string,
 	i: string,
 	liveBindings: boolean,
-	freeze: boolean
+	freeze: boolean,
+	namespaceToStringTag: boolean
 ) {
 	return (
-		`${i}var n${_}=${_}Object.create(null);${n}` +
+		`${i}var n${_}=${_}${
+			namespaceToStringTag
+				? `{__proto__:${_}null,${_}[Symbol.toStringTag]:${_}'Module'}`
+				: 'Object.create(null)'
+		};${n}` +
 		`${i}if${_}(e)${_}{${n}` +
 		`${i}${t}Object.keys(e).forEach(function${_}(k)${_}{${n}` +
 		(liveBindings ? copyPropertyLiveBinding : copyPropertyStatic)(_, n, t, i + t + t) +

test/chunking-form/samples/namespace-tostring/dynamic-import-default-mode/_config.js

@@ -0,0 +1,10 @@
+module.exports = {
+	description:
+		'adds Symbol.toStringTag property to dynamic imports of entry chunks with default export mode',
+	options: {
+		input: ['main', 'foo'],
+		output: {
+			namespaceToStringTag: true
+		}
+	}
+};

test/chunking-form/samples/namespace-tostring/dynamic-import-default-mode/_expected/amd/foo.js

@@ -0,0 +1,7 @@
+define(function () { 'use strict';
+
+	var foo = 42;
+
+	return foo;
+
+});

test/chunking-form/samples/namespace-tostring/dynamic-import-default-mode/_expected/amd/main.js

@@ -0,0 +1,9 @@
+define(['require'], function (require) { 'use strict';
+
+	function _interopNamespaceDefaultOnly(e) {
+		return Object.freeze({__proto__: null, [Symbol.toStringTag]: 'Module', 'default': e});
+	}
+
+	new Promise(function (resolve, reject) { require(['./foo'], function (m) { resolve(/*#__PURE__*/_interopNamespaceDefaultOnly(m)); }, reject) }).then(console.log);
+
+});

test/chunking-form/samples/namespace-tostring/dynamic-import-default-mode/_expected/cjs/foo.js

@@ -0,0 +1,5 @@
+'use strict';
+
+var foo = 42;
+
+module.exports = foo;

test/chunking-form/samples/namespace-tostring/dynamic-import-default-mode/_expected/cjs/main.js

@@ -0,0 +1,7 @@
+'use strict';
+
+function _interopNamespaceDefaultOnly(e) {
+	return Object.freeze({__proto__: null, [Symbol.toStringTag]: 'Module', 'default': e});
+}
+
+Promise.resolve().then(function () { return /*#__PURE__*/_interopNamespaceDefaultOnly(require('./foo.js')); }).then(console.log);

test/chunking-form/samples/namespace-tostring/dynamic-import-default-mode/_expected/es/foo.js

@@ -0,0 +1,3 @@
+var foo = 42;
+
+export default foo;

test/chunking-form/samples/namespace-tostring/dynamic-import-default-mode/_expected/es/main.js

@@ -0,0 +1 @@
+import('./foo.js').then(console.log);

test/chunking-form/samples/namespace-tostring/dynamic-import-default-mode/_expected/system/foo.js

@@ -0,0 +1,10 @@
+System.register([], function (exports) {
+	'use strict';
+	return {
+		execute: function () {
+
+			var foo = exports('default', 42);
+
+		}
+	};
+});