webpack/lib/ids/HashedModuleIdsPlugin.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 { validate } = require("schema-utils");
const schema = require("../../schemas/plugins/HashedModuleIdsPlugin.json");
const {
	compareModulesByPreOrderIndexOrIdentifier
} = require("../util/comparators");
const createHash = require("../util/createHash");
const { getUsedModuleIds, getFullModuleName } = require("./IdHelpers");

/** @typedef {import("../../declarations/plugins/HashedModuleIdsPlugin").HashedModuleIdsPluginOptions} HashedModuleIdsPluginOptions */

class HashedModuleIdsPlugin {
	/**
	 * @param {HashedModuleIdsPluginOptions=} options options object
	 */
	constructor(options = {}) {
		validate(schema, options, {
			name: "Hashed Module Ids Plugin",
			baseDataPath: "options"
		});

		/** @type {HashedModuleIdsPluginOptions} */
		this.options = {
			context: null,
			hashFunction: "md4",
			hashDigest: "base64",
			hashDigestLength: 4,
			...options
		};
	}

	apply(compiler) {
		const options = this.options;
		compiler.hooks.compilation.tap("HashedModuleIdsPlugin", compilation => {
			compilation.hooks.moduleIds.tap("HashedModuleIdsPlugin", modules => {
				const chunkGraph = compilation.chunkGraph;
				const context = this.options.context
					? this.options.context
					: compiler.context;

				const usedIds = getUsedModuleIds(compilation);
				const modulesInNaturalOrder = Array.from(modules)
					.filter(m => {
						if (!m.needId) return false;
						if (chunkGraph.getNumberOfModuleChunks(m) === 0) return false;
						return chunkGraph.getModuleId(module) === null;
					})
					.sort(
						compareModulesByPreOrderIndexOrIdentifier(compilation.moduleGraph)
					);
				for (const module of modulesInNaturalOrder) {
					const ident = getFullModuleName(module, context, compiler.root);
					const hash = createHash(options.hashFunction);
					hash.update(ident || "");
					const hashId = /** @type {string} */ (hash.digest(
						options.hashDigest
					));
					let len = options.hashDigestLength;
					while (usedIds.has(hashId.substr(0, len))) len++;
					const moduleId = hashId.substr(0, len);
					chunkGraph.setModuleId(module, moduleId);
					usedIds.add(moduleId);
				}
			});
		});
	}
}

module.exports = HashedModuleIdsPlugin;