webpack/lib/async-modules/InferAsyncModulesPlugin.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 HarmonyImportDependency = require("../dependencies/HarmonyImportDependency");

/** @typedef {import("../Compiler")} Compiler */
/** @typedef {import("../Module")} Module */

class InferAsyncModulesPlugin {
	/**
	 * Apply the plugin
	 * @param {Compiler} compiler the compiler instance
	 * @returns {void}
	 */
	apply(compiler) {
		compiler.hooks.compilation.tap("InferAsyncModulesPlugin", compilation => {
			const { moduleGraph } = compilation;
			compilation.hooks.finishModules.tap(
				"InferAsyncModulesPlugin",
				modules => {
					/** @type {Set<Module>} */
					const queue = new Set();
					for (const module of modules) {
						if (module.buildMeta && module.buildMeta.async) {
							queue.add(module);
						}
					}
					for (const module of queue) {
						moduleGraph.setAsync(module);
						for (const [
							originModule,
							connections
						] of moduleGraph.getIncomingConnectionsByOriginModule(module)) {
							if (
								connections.some(
									c =>
										c.dependency instanceof HarmonyImportDependency &&
										c.isTargetActive(undefined)
								)
							) {
								queue.add(originModule);
							}
						}
					}
				}
			);
		});
	}
}

module.exports = InferAsyncModulesPlugin;