webpack/lib/dependencies/HarmonyExportImportedSpecifierDependency.js

Packs CommonJs/AMD modules for the browser. Allows to split your codebase into multiple bundles, which can be loaded on demand. Support loaders to preprocess files, i.e. json, jsx, es7, css, less, ... and your custom stuff.

/*
	MIT License http://www.opensource.org/licenses/mit-license.php
	Author Tobias Koppers @sokra
*/

"use strict";

const Dependency = require("../Dependency");
const { UsageState } = require("../ExportsInfo");
const HarmonyLinkingError = require("../HarmonyLinkingError");
const InitFragment = require("../InitFragment");
const RuntimeGlobals = require("../RuntimeGlobals");
const Template = require("../Template");
const makeSerializable = require("../util/makeSerializable");
const propertyAccess = require("../util/propertyAccess");
const HarmonyExportInitFragment = require("./HarmonyExportInitFragment");
const HarmonyImportDependency = require("./HarmonyImportDependency");
const processExportInfo = require("./processExportInfo");

/** @typedef {import("webpack-sources").ReplaceSource} ReplaceSource */
/** @typedef {import("../ChunkGraph")} ChunkGraph */
/** @typedef {import("../Dependency")} Dependency */
/** @typedef {import("../Dependency").ExportsSpec} ExportsSpec */
/** @typedef {import("../Dependency").ReferencedExport} ReferencedExport */
/** @typedef {import("../Dependency").UpdateHashContext} UpdateHashContext */
/** @typedef {import("../DependencyTemplate").DependencyTemplateContext} DependencyTemplateContext */
/** @typedef {import("../ExportsInfo")} ExportsInfo */
/** @typedef {import("../ExportsInfo").ExportInfo} ExportInfo */
/** @typedef {import("../Module")} Module */
/** @typedef {import("../ModuleGraph")} ModuleGraph */
/** @typedef {import("../ModuleGraphConnection")} ModuleGraphConnection */
/** @typedef {import("../ModuleGraphConnection").ConnectionState} ConnectionState */
/** @typedef {import("../RuntimeTemplate")} RuntimeTemplate */
/** @typedef {import("../WebpackError")} WebpackError */
/** @typedef {import("../util/Hash")} Hash */
/** @typedef {import("../util/runtime").RuntimeSpec} RuntimeSpec */

/** @typedef {"missing"|"unused"|"empty-star"|"reexport-dynamic-default"|"reexport-named-default"|"reexport-namespace-object"|"reexport-fake-namespace-object"|"reexport-undefined"|"normal-reexport"|"dynamic-reexport"} ExportModeType */

const idsSymbol = Symbol("HarmonyExportImportedSpecifierDependency.ids");

class NormalReexportItem {
	/**
	 * @param {string} name export name
	 * @param {string[]} ids reexported ids from other module
	 * @param {ExportInfo=} exportInfo export info from other module
	 * @param {boolean=} checked true, if it should be checked at runtime if this export exists
	 */
	constructor(name, ids, exportInfo, checked) {
		this.name = name;
		this.ids = ids;
		this.exportInfo = exportInfo;
		this.checked = checked;
	}
}

class ExportMode {
	/**
	 * @param {ExportModeType} type type of the mode
	 */
	constructor(type) {
		/** @type {ExportModeType} */
		this.type = type;

		// for "normal-reexport":
		/** @type {NormalReexportItem[] | null} */
		this.items = null;

		// for "reexport-named-default" | "reexport-fake-namespace-object" | "reexport-namespace-object"
		/** @type {string|null} */
		this.name = null;
		/** @type {ExportInfo | null} */
		this.partialNamespaceExportInfo = null;

		// for "dynamic-reexport":
		/** @type {Set<string> | null} */
		this.ignored = null;

		// for "missing":
		/** @type {string | null} */
		this.userRequest = null;

		// for "reexport-fake-namespace-object":
		/** @type {number} */
		this.fakeType = 0;
	}
}

class HarmonyExportImportedSpecifierDependency extends HarmonyImportDependency {
	/**
	 * @param {string} request the request string
	 * @param {number} sourceOrder the order in the original source file
	 * @param {string[]} ids the requested export name of the imported module
	 * @param {string | null} name the export name of for this module
	 * @param {Set<string>} activeExports other named exports in the module
	 * @param {Iterable<HarmonyExportImportedSpecifierDependency>} otherStarExports other star exports in the module
	 * @param {boolean} strictExportPresence when true, missing exports in the imported module lead to errors instead of warnings
	 */
	constructor(
		request,
		sourceOrder,
		ids,
		name,
		activeExports,
		otherStarExports,
		strictExportPresence
	) {
		super(request, sourceOrder);

		this.ids = ids;
		this.name = name;
		this.activeExports = activeExports;
		this.otherStarExports = otherStarExports;
		this.strictExportPresence = strictExportPresence;
	}

	// TODO webpack 6 remove
	get id() {
		throw new Error("id was renamed to ids and type changed to string[]");
	}

	// TODO webpack 6 remove
	getId() {
		throw new Error("id was renamed to ids and type changed to string[]");
	}

	// TODO webpack 6 remove
	setId() {
		throw new Error("id was renamed to ids and type changed to string[]");
	}

	get type() {
		return "harmony export imported specifier";
	}

	/**
	 * @param {ModuleGraph} moduleGraph the module graph
	 * @returns {string[]} the imported id
	 */
	getIds(moduleGraph) {
		return moduleGraph.getMeta(this)[idsSymbol] || this.ids;
	}

	/**
	 * @param {ModuleGraph} moduleGraph the module graph
	 * @param {string[]} ids the imported ids
	 * @returns {void}
	 */
	setIds(moduleGraph, ids) {
		moduleGraph.getMeta(this)[idsSymbol] = ids;
	}

	/**
	 * @param {ModuleGraph} moduleGraph the module graph
	 * @param {RuntimeSpec} runtime the runtime
	 * @returns {ExportMode} the export mode
	 */
	getMode(moduleGraph, runtime) {
		const name = this.name;
		const ids = this.getIds(moduleGraph);
		const parentModule = moduleGraph.getParentModule(this);
		const importedModule = moduleGraph.getModule(this);
		const exportsInfo = moduleGraph.getExportsInfo(parentModule);

		if (!importedModule) {
			const mode = new ExportMode("missing");

			mode.userRequest = this.userRequest;

			return mode;
		}

		if (
			name
				? exportsInfo.getUsed(name, runtime) === UsageState.Unused
				: exportsInfo.isUsed(runtime) === false
		) {
			const mode = new ExportMode("unused");

			mode.name = name || "*";

			return mode;
		}

		const importedExportsType = importedModule.getExportsType(
			moduleGraph,
			parentModule.buildMeta.strictHarmonyModule
		);

		// Special handling for reexporting the default export
		// from non-namespace modules
		if (name && ids.length > 0 && ids[0] === "default") {
			switch (importedExportsType) {
				case "dynamic": {
					const mode = new ExportMode("reexport-dynamic-default");

					mode.name = name;

					return mode;
				}
				case "default-only":
				case "default-with-named": {
					const exportInfo = exportsInfo.getReadOnlyExportInfo(name);
					const mode = new ExportMode("reexport-named-default");

					mode.name = name;
					mode.partialNamespaceExportInfo = exportInfo;

					return mode;
				}
			}
		}

		// reexporting with a fixed name
		if (name) {
			let mode;
			const exportInfo = exportsInfo.getReadOnlyExportInfo(name);

			if (ids.length > 0) {
				// export { name as name }
				switch (importedExportsType) {
					case "default-only":
						mode = new ExportMode("reexport-undefined");
						mode.name = name;
						break;
					default:
						mode = new ExportMode("normal-reexport");
						mode.items = [new NormalReexportItem(name, ids, exportInfo, false)];
						break;
				}
			} else {
				// export * as name
				switch (importedExportsType) {
					case "default-only":
						mode = new ExportMode("reexport-fake-namespace-object");
						mode.name = name;
						mode.partialNamespaceExportInfo = exportInfo;
						mode.fakeType = 0;
						break;
					case "default-with-named":
						mode = new ExportMode("reexport-fake-namespace-object");
						mode.name = name;
						mode.partialNamespaceExportInfo = exportInfo;
						mode.fakeType = 2;
						break;
					case "dynamic":
						mode = new ExportMode("reexport-fake-namespace-object");
						mode.name = name;
						mode.partialNamespaceExportInfo = exportInfo;
						mode.fakeType = 6;
						break;
					default:
						mode = new ExportMode("reexport-namespace-object");
						mode.name = name;
						mode.partialNamespaceExportInfo = exportInfo;
				}
			}

			return mode;
		}

		// Star reexporting

		const { ignoredExports, exports, checked } = this.getStarReexports(
			moduleGraph,
			runtime,
			exportsInfo,
			importedModule
		);
		if (!exports) {
			// We have too few info about the modules
			// Delegate the logic to the runtime code

			const mode = new ExportMode("dynamic-reexport");
			mode.ignored = ignoredExports;

			return mode;
		}

		if (exports.size === 0) {
			const mode = new ExportMode("empty-star");

			return mode;
		}

		const mode = new ExportMode("normal-reexport");

		mode.items = Array.from(
			exports,
			exportName =>
				new NormalReexportItem(
					exportName,
					[exportName],
					exportsInfo.getReadOnlyExportInfo(exportName),
					checked.has(exportName)
				)
		);

		return mode;
	}

	/**
	 * @param {ModuleGraph} moduleGraph the module graph
	 * @param {RuntimeSpec} runtime the runtime
	 * @param {ExportsInfo} exportsInfo exports info about the current module (optional)
	 * @param {Module} importedModule the imported module (optional)
	 * @returns {{exports?: Set<string>, checked?: Set<string>, ignoredExports: Set<string>}} information
	 */
	getStarReexports(
		moduleGraph,
		runtime,
		exportsInfo = moduleGraph.getExportsInfo(moduleGraph.getParentModule(this)),
		importedModule = moduleGraph.getModule(this)
	) {
		const importedExportsInfo = moduleGraph.getExportsInfo(importedModule);

		const noExtraExports =
			importedExportsInfo.otherExportsInfo.provided === false;
		const noExtraImports =
			exportsInfo.otherExportsInfo.getUsed(runtime) === UsageState.Unused;

		const ignoredExports = new Set([
			"default",
			...this.activeExports,
			...this._discoverActiveExportsFromOtherStarExports(moduleGraph).keys()
		]);

		if (!noExtraExports && !noExtraImports) {
			return {
				ignoredExports
			};
		}

		/** @type {Set<string>} */
		const exports = new Set();
		/** @type {Set<string>} */
		const checked = new Set();

		if (noExtraImports) {
			for (const exportInfo of exportsInfo.orderedExports) {
				const name = exportInfo.name;
				if (ignoredExports.has(name)) continue;
				if (exportInfo.getUsed(runtime) === UsageState.Unused) continue;
				const importedExportInfo = importedExportsInfo.getReadOnlyExportInfo(
					name
				);
				if (importedExportInfo.provided === false) continue;
				exports.add(name);
				if (importedExportInfo.provided === true) continue;
				checked.add(name);
			}
		} else if (noExtraExports) {
			for (const importedExportInfo of importedExportsInfo.orderedExports) {
				const name = importedExportInfo.name;
				if (ignoredExports.has(name)) continue;
				if (importedExportInfo.provided === false) continue;
				const exportInfo = exportsInfo.getReadOnlyExportInfo(name);
				if (exportInfo.getUsed(runtime) === UsageState.Unused) continue;
				exports.add(name);
				if (importedExportInfo.provided === true) continue;
				checked.add(name);
			}
		}

		return { ignoredExports, exports, checked };
	}

	/**
	 * @param {ModuleGraph} moduleGraph module graph
	 * @returns {function(ModuleGraphConnection, RuntimeSpec): ConnectionState} function to determine if the connection is active
	 */
	getCondition(moduleGraph) {
		return (connection, runtime) => {
			const mode = this.getMode(moduleGraph, runtime);
			return mode.type !== "unused" && mode.type !== "empty-star";
		};
	}

	/**
	 * Returns list of exports referenced by this dependency
	 * @param {ModuleGraph} moduleGraph module graph
	 * @param {RuntimeSpec} runtime the runtime for which the module is analysed
	 * @returns {(string[] | ReferencedExport)[]} referenced exports
	 */
	getReferencedExports(moduleGraph, runtime) {
		const mode = this.getMode(moduleGraph, runtime);

		switch (mode.type) {
			case "missing":
			case "unused":
			case "empty-star":
			case "reexport-undefined":
				return Dependency.NO_EXPORTS_REFERENCED;

			case "reexport-dynamic-default":
				return Dependency.EXPORTS_OBJECT_REFERENCED;

			case "reexport-named-default": {
				if (!mode.partialNamespaceExportInfo)
					return Dependency.EXPORTS_OBJECT_REFERENCED;
				/** @type {string[][]} */
				const referencedExports = [];
				processExportInfo(
					runtime,
					referencedExports,
					[],
					/** @type {ExportInfo} */ (mode.partialNamespaceExportInfo)
				);
				return referencedExports;
			}

			case "reexport-namespace-object":
			case "reexport-fake-namespace-object": {
				if (!mode.partialNamespaceExportInfo)
					return Dependency.EXPORTS_OBJECT_REFERENCED;
				/** @type {string[][]} */
				const referencedExports = [];
				processExportInfo(
					runtime,
					referencedExports,
					[],
					/** @type {ExportInfo} */ (mode.partialNamespaceExportInfo),
					mode.type === "reexport-fake-namespace-object"
				);
				return referencedExports;
			}

			case "dynamic-reexport":
				return Dependency.EXPORTS_OBJECT_REFERENCED;

			case "normal-reexport": {
				const referencedExports = [];
				for (const { ids, exportInfo } of mode.items) {
					processExportInfo(runtime, referencedExports, ids, exportInfo, false);
				}
				return referencedExports;
			}

			default:
				throw new Error(`Unknown mode ${mode.type}`);
		}
	}

	/**
	 * @param {ModuleGraph} moduleGraph the module graph
	 * @returns {Map<string, HarmonyExportImportedSpecifierDependency>} exported names and their origin dependency
	 */
	_discoverActiveExportsFromOtherStarExports(moduleGraph) {
		if (!this.otherStarExports) {
			return new Map();
		}

		const result = new Map();
		// try to learn impossible exports from other star exports with provided exports
		for (const otherStarExport of this.otherStarExports) {
			const otherImportedModule = moduleGraph.getModule(otherStarExport);
			if (otherImportedModule) {
				const exportsInfo = moduleGraph.getExportsInfo(otherImportedModule);
				for (const exportInfo of exportsInfo.exports) {
					if (exportInfo.provided === true && !result.has(exportInfo.name)) {
						result.set(exportInfo.name, otherStarExport);
					}
				}
			}
		}

		return result;
	}

	/**
	 * Returns the exported names
	 * @param {ModuleGraph} moduleGraph module graph
	 * @returns {ExportsSpec | undefined} export names
	 */
	getExports(moduleGraph) {
		const mode = this.getMode(moduleGraph, undefined);

		switch (mode.type) {
			case "missing":
				return undefined;
			case "dynamic-reexport": {
				const from = moduleGraph.getConnection(this);
				return {
					exports: true,
					from,
					canMangle: false,
					excludeExports: mode.ignored,
					dependencies: [from.module]
				};
			}
			case "empty-star":
				return {
					exports: [],
					dependencies: [moduleGraph.getModule(this)]
				};
			case "normal-reexport": {
				const from = moduleGraph.getConnection(this);
				return {
					exports: Array.from(mode.items, item => ({
						name: item.name,
						from,
						export: item.ids
					})),
					dependencies: [from.module]
				};
			}
			case "reexport-dynamic-default": {
				{
					const from = moduleGraph.getConnection(this);
					return {
						exports: [
							{
								name: mode.name,
								from,
								export: ["default"]
							}
						],
						dependencies: [from.module]
					};
				}
			}
			case "reexport-undefined":
				return {
					exports: [mode.name],
					dependencies: [moduleGraph.getModule(this)]
				};
			case "reexport-fake-namespace-object": {
				const from = moduleGraph.getConnection(this);
				return {
					exports: [
						{
							name: mode.name,
							from,
							export: null,
							exports: [
								{
									name: "default",
									canMangle: false,
									from,
									export: null
								}
							]
						}
					],
					dependencies: [from.module]
				};
			}
			case "reexport-namespace-object": {
				const from = moduleGraph.getConnection(this);
				return {
					exports: [
						{
							name: mode.name,
							from,
							export: null
						}
					],
					dependencies: [from.module]
				};
			}
			case "reexport-named-default": {
				const from = moduleGraph.getConnection(this);
				return {
					exports: [
						{
							name: mode.name,
							from,
							export: ["default"]
						}
					],
					dependencies: [from.module]
				};
			}
			default:
				throw new Error(`Unknown mode ${mode.type}`);
		}
	}

	/**
	 * Returns warnings
	 * @param {ModuleGraph} moduleGraph module graph
	 * @returns {WebpackError[]} warnings
	 */
	getWarnings(moduleGraph) {
		if (
			this.strictExportPresence ||
			moduleGraph.getParentModule(this).buildMeta.strictHarmonyModule
		) {
			return null;
		}

		return this._getErrors(moduleGraph);
	}

	/**
	 * Returns errors
	 * @param {ModuleGraph} moduleGraph module graph
	 * @returns {WebpackError[]} errors
	 */
	getErrors(moduleGraph) {
		if (
			this.strictExportPresence ||
			moduleGraph.getParentModule(this).buildMeta.strictHarmonyModule
		) {
			return this._getErrors(moduleGraph);
		}

		return null;
	}

	/**
	 * @param {ModuleGraph} moduleGraph module graph
	 * @returns {WebpackError[] | undefined} errors
	 */
	_getErrors(moduleGraph) {
		const ids = this.getIds(moduleGraph);
		let errors = this.getLinkingErrors(
			moduleGraph,
			ids,
			`(reexported as '${this.name}')`
		);
		if (ids.length === 0 && this.name === null) {
			const potentialConflicts = this._discoverActiveExportsFromOtherStarExports(
				moduleGraph
			);
			if (potentialConflicts.size > 0) {
				const importedModule = moduleGraph.getModule(this);
				if (importedModule) {
					const exportsInfo = moduleGraph.getExportsInfo(importedModule);
					const conflicts = new Map();
					for (const exportInfo of exportsInfo.orderedExports) {
						if (exportInfo.provided !== true) continue;
						if (exportInfo.name === "default") continue;
						if (this.activeExports.has(exportInfo.name)) continue;
						const conflictingDependency = potentialConflicts.get(
							exportInfo.name
						);
						if (!conflictingDependency) continue;
						const target = exportInfo.getTerminalBinding(moduleGraph);
						if (!target) continue;
						const conflictingModule = moduleGraph.getModule(
							conflictingDependency
						);
						if (conflictingModule === importedModule) continue;
						const conflictingExportInfo = moduleGraph.getExportInfo(
							conflictingModule,
							exportInfo.name
						);
						const conflictingTarget = conflictingExportInfo.getTerminalBinding(
							moduleGraph
						);
						if (!conflictingTarget) continue;
						if (target === conflictingTarget) continue;
						const list = conflicts.get(conflictingDependency.request);
						if (list === undefined) {
							conflicts.set(conflictingDependency.request, [exportInfo.name]);
						} else {
							list.push(exportInfo.name);
						}
					}
					for (const [request, exports] of conflicts) {
						if (!errors) errors = [];
						errors.push(
							new HarmonyLinkingError(
								`The requested module '${
									this.request
								}' contains conflicting star exports for the ${
									exports.length > 1 ? "names" : "name"
								} ${exports
									.map(e => `'${e}'`)
									.join(", ")} with the previous requested module '${request}'`
							)
						);
					}
				}
			}
		}
		return errors;
	}

	/**
	 * Update the hash
	 * @param {Hash} hash hash to be updated
	 * @param {UpdateHashContext} context context
	 * @returns {void}
	 */
	updateHash(hash, context) {
		const { chunkGraph, runtime } = context;
		super.updateHash(hash, context);

		const mode = this.getMode(chunkGraph.moduleGraph, runtime);

		hash.update(mode.type);
		if (mode.items) {
			for (const item of mode.items) {
				hash.update(item.name);
				hash.update(item.ids.join());
				if (item.checked) hash.update("checked");
			}
		}
		if (mode.ignored) {
			hash.update("ignored");
			for (const k of mode.ignored) {
				hash.update(k);
			}
		}
		hash.update(mode.name || "");
	}

	serialize(context) {
		const { write } = context;

		write(this.ids);
		write(this.name);
		write(this.activeExports);
		write(this.otherStarExports);
		write(this.strictExportPresence);

		super.serialize(context);
	}

	deserialize(context) {
		const { read } = context;

		this.ids = read();
		this.name = read();
		this.activeExports = read();
		this.otherStarExports = read();
		this.strictExportPresence = read();

		super.deserialize(context);
	}
}

makeSerializable(
	HarmonyExportImportedSpecifierDependency,
	"webpack/lib/dependencies/HarmonyExportImportedSpecifierDependency"
);

module.exports = HarmonyExportImportedSpecifierDependency;

HarmonyExportImportedSpecifierDependency.Template = class HarmonyExportImportedSpecifierDependencyTemplate extends HarmonyImportDependency.Template {
	/**
	 * @param {Dependency} dependency the dependency for which the template should be applied
	 * @param {ReplaceSource} source the current replace source which can be modified
	 * @param {DependencyTemplateContext} templateContext the context object
	 * @returns {void}
	 */
	apply(dependency, source, templateContext) {
		const { moduleGraph, runtime, concatenationScope } = templateContext;

		const dep = /** @type {HarmonyExportImportedSpecifierDependency} */ (dependency);

		const mode = dep.getMode(moduleGraph, runtime);

		if (concatenationScope) {
			switch (mode.type) {
				case "reexport-undefined":
					concatenationScope.registerRawExport(
						mode.name,
						"/* reexport non-default export from non-harmony */ undefined"
					);
			}
			return;
		}

		if (mode.type !== "unused" && mode.type !== "empty-star") {
			super.apply(dependency, source, templateContext);

			this._addExportFragments(
				templateContext.initFragments,
				dep,
				mode,
				templateContext.module,
				moduleGraph,
				runtime,
				templateContext.runtimeTemplate,
				templateContext.runtimeRequirements
			);
		}
	}

	/**
	 * @param {InitFragment[]} initFragments target array for init fragments
	 * @param {HarmonyExportImportedSpecifierDependency} dep dependency
	 * @param {ExportMode} mode the export mode
	 * @param {Module} module the current module
	 * @param {ModuleGraph} moduleGraph the module graph
	 * @param {RuntimeSpec} runtime the runtime
	 * @param {RuntimeTemplate} runtimeTemplate the runtime template
	 * @param {Set<string>} runtimeRequirements runtime requirements
	 * @returns {void}
	 */
	_addExportFragments(
		initFragments,
		dep,
		mode,
		module,
		moduleGraph,
		runtime,
		runtimeTemplate,
		runtimeRequirements
	) {
		const importedModule = moduleGraph.getModule(dep);
		const importVar = dep.getImportVar(moduleGraph);

		switch (mode.type) {
			case "missing":
			case "empty-star":
				initFragments.push(
					new InitFragment(
						"/* empty/unused harmony star reexport */\n",
						InitFragment.STAGE_HARMONY_EXPORTS,
						1
					)
				);
				break;

			case "unused":
				initFragments.push(
					new InitFragment(
						`${Template.toNormalComment(
							`unused harmony reexport ${mode.name}`
						)}\n`,
						InitFragment.STAGE_HARMONY_EXPORTS,
						1
					)
				);
				break;

			case "reexport-dynamic-default":
				initFragments.push(
					this.getReexportFragment(
						module,
						"reexport default from dynamic",
						moduleGraph.getExportsInfo(module).getUsedName(mode.name, runtime),
						importVar,
						null,
						runtimeRequirements
					)
				);
				break;

			case "reexport-fake-namespace-object":
				initFragments.push(
					...this.getReexportFakeNamespaceObjectFragments(
						module,
						moduleGraph.getExportsInfo(module).getUsedName(mode.name, runtime),
						importVar,
						mode.fakeType,
						runtimeRequirements
					)
				);
				break;

			case "reexport-undefined":
				initFragments.push(
					this.getReexportFragment(
						module,
						"reexport non-default export from non-harmony",
						moduleGraph.getExportsInfo(module).getUsedName(mode.name, runtime),
						"undefined",
						"",
						runtimeRequirements
					)
				);
				break;

			case "reexport-named-default":
				initFragments.push(
					this.getReexportFragment(
						module,
						"reexport default export from named module",
						moduleGraph.getExportsInfo(module).getUsedName(mode.name, runtime),
						importVar,
						"",
						runtimeRequirements
					)
				);
				break;

			case "reexport-namespace-object":
				initFragments.push(
					this.getReexportFragment(
						module,
						"reexport module object",
						moduleGraph.getExportsInfo(module).getUsedName(mode.name, runtime),
						importVar,
						"",
						runtimeRequirements
					)
				);
				break;

			case "normal-reexport":
				for (const { name, ids, checked } of mode.items) {
					if (checked) {
						initFragments.push(
							new InitFragment(
								"/* harmony reexport (checked) */ " +
									this.getConditionalReexportStatement(
										module,
										name,
										importVar,
										ids,
										runtimeRequirements
									),
								InitFragment.STAGE_HARMONY_IMPORTS,
								dep.sourceOrder
							)
						);
					} else {
						initFragments.push(
							this.getReexportFragment(
								module,
								"reexport safe",
								moduleGraph.getExportsInfo(module).getUsedName(name, runtime),
								importVar,
								moduleGraph
									.getExportsInfo(importedModule)
									.getUsedName(ids, runtime),
								runtimeRequirements
							)
						);
					}
				}
				break;

			case "dynamic-reexport": {
				const ignored = mode.ignored;
				const modern =
					runtimeTemplate.supportsConst() &&
					runtimeTemplate.supportsArrowFunction();
				let content =
					"/* harmony reexport (unknown) */ var __WEBPACK_REEXPORT_OBJECT__ = {};\n" +
					`/* harmony reexport (unknown) */ for(${
						modern ? "const" : "var"
					} __WEBPACK_IMPORT_KEY__ in ${importVar}) `;

				// Filter out exports which are defined by other exports
				// and filter out default export because it cannot be reexported with *
				if (ignored.size > 1) {
					content +=
						"if(" +
						JSON.stringify(Array.from(ignored)) +
						".indexOf(__WEBPACK_IMPORT_KEY__) < 0) ";
				} else if (ignored.size === 1) {
					content += `if(__WEBPACK_IMPORT_KEY__ !== ${JSON.stringify(
						ignored.values().next().value
					)}) `;
				}

				content += `__WEBPACK_REEXPORT_OBJECT__[__WEBPACK_IMPORT_KEY__] = `;
				if (modern) {
					content += `() => ${importVar}[__WEBPACK_IMPORT_KEY__]`;
				} else {
					content += `function(key) { return ${importVar}[key]; }.bind(0, __WEBPACK_IMPORT_KEY__)`;
				}

				runtimeRequirements.add(RuntimeGlobals.exports);
				runtimeRequirements.add(RuntimeGlobals.definePropertyGetters);

				const exportsName = module.exportsArgument;
				initFragments.push(
					new InitFragment(
						`${content}\n/* harmony reexport (unknown) */ ${RuntimeGlobals.definePropertyGetters}(${exportsName}, __WEBPACK_REEXPORT_OBJECT__);\n`,
						InitFragment.STAGE_HARMONY_IMPORTS,
						dep.sourceOrder
					)
				);
				break;
			}

			default:
				throw new Error(`Unknown mode ${mode.type}`);
		}
	}

	getReexportFragment(
		module,
		comment,
		key,
		name,
		valueKey,
		runtimeRequirements
	) {
		const returnValue = this.getReturnValue(name, valueKey);

		runtimeRequirements.add(RuntimeGlobals.exports);
		runtimeRequirements.add(RuntimeGlobals.definePropertyGetters);

		const map = new Map();
		map.set(key, `/* ${comment} */ ${returnValue}`);

		return new HarmonyExportInitFragment(module.exportsArgument, map);
	}

	getReexportFakeNamespaceObjectFragments(
		module,
		key,
		name,
		fakeType,
		runtimeRequirements
	) {
		runtimeRequirements.add(RuntimeGlobals.exports);
		runtimeRequirements.add(RuntimeGlobals.definePropertyGetters);
		runtimeRequirements.add(RuntimeGlobals.createFakeNamespaceObject);

		const map = new Map();
		map.set(
			key,
			`/* reexport fake namespace object from non-harmony */ ${name}_namespace_cache || (${name}_namespace_cache = ${
				RuntimeGlobals.createFakeNamespaceObject
			}(${name}${fakeType ? `, ${fakeType}` : ""}))`
		);

		return [
			new InitFragment(
				`var ${name}_namespace_cache;\n`,
				InitFragment.STAGE_CONSTANTS,
				-1,
				`${name}_namespace_cache`
			),
			new HarmonyExportInitFragment(module.exportsArgument, map)
		];
	}

	getConditionalReexportStatement(
		module,
		key,
		name,
		valueKey,
		runtimeRequirements
	) {
		if (valueKey === false) {
			return "/* unused export */\n";
		}

		const exportsName = module.exportsArgument;
		const returnValue = this.getReturnValue(name, valueKey);

		runtimeRequirements.add(RuntimeGlobals.exports);
		runtimeRequirements.add(RuntimeGlobals.definePropertyGetters);
		runtimeRequirements.add(RuntimeGlobals.hasOwnProperty);

		return `if(${RuntimeGlobals.hasOwnProperty}(${name}, ${JSON.stringify(
			valueKey[0]
		)})) ${
			RuntimeGlobals.definePropertyGetters
		}(${exportsName}, { ${JSON.stringify(
			key
		)}: function() { return ${returnValue}; } });\n`;
	}

	getReturnValue(name, valueKey) {
		if (valueKey === null) {
			return `${name}_default.a`;
		}

		if (valueKey === "") {
			return name;
		}

		if (valueKey === false) {
			return "/* unused export */ undefined";
		}

		return `${name}${propertyAccess(valueKey)}`;
	}
};