webpack/lib/ExternalsPlugin.js

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

"use strict";

const { ModuleExternalInitFragment } = require("./ExternalModule");
const ExternalModuleFactoryPlugin = require("./ExternalModuleFactoryPlugin");
const ConcatenatedModule = require("./optimize/ConcatenatedModule");

/** @typedef {import("../declarations/WebpackOptions").Externals} Externals */
/** @typedef {import("./Compiler")} Compiler */
/** @typedef {import("./optimize/ConcatenatedModule").ConcatenatedModuleInfo} ConcatenatedModuleInfo */

const PLUGIN_NAME = "ExternalsPlugin";

class ExternalsPlugin {
	/**
	 * @param {string | undefined} type default external type
	 * @param {Externals} externals externals config
	 */
	constructor(type, externals) {
		this.type = type;
		this.externals = externals;
	}

	/**
	 * Apply the plugin
	 * @param {Compiler} compiler the compiler instance
	 * @returns {void}
	 */
	apply(compiler) {
		compiler.hooks.compile.tap(PLUGIN_NAME, ({ normalModuleFactory }) => {
			new ExternalModuleFactoryPlugin(this.type, this.externals).apply(
				normalModuleFactory
			);
		});

		compiler.hooks.compilation.tap(PLUGIN_NAME, (compilation) => {
			const { concatenatedModuleInfo } =
				ConcatenatedModule.getCompilationHooks(compilation);
			concatenatedModuleInfo.tap(PLUGIN_NAME, (updatedInfo, moduleInfo) => {
				const rawExportMap =
					/** @type {ConcatenatedModuleInfo} */ updatedInfo.rawExportMap;

				if (!rawExportMap) {
					return;
				}

				const chunkInitFragments =
					/** @type {ConcatenatedModuleInfo} */ moduleInfo.chunkInitFragments;
				const moduleExternalInitFragments = chunkInitFragments
					? chunkInitFragments.filter(
							(fragment) => fragment instanceof ModuleExternalInitFragment
						)
					: [];

				let initFragmentChanged = false;

				for (const fragment of moduleExternalInitFragments) {
					const imported = fragment.getImported();

					if (Array.isArray(imported)) {
						const newImported = imported.map(([specifier, finalName]) => [
							specifier,
							rawExportMap.has(specifier)
								? rawExportMap.get(specifier)
								: finalName
						]);
						fragment.setImported(newImported);
						initFragmentChanged = true;
					}
				}

				if (initFragmentChanged) {
					return true;
				}
			});
		});
	}
}

module.exports = ExternalsPlugin;