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 {
	compareModulesByPreOrderIndexOrIdentifier
} = require("../util/comparators");
const createSchemaValidation = require("../util/create-schema-validation");
const createHash = require("../util/createHash");
const { getUsedModuleIds, getFullModuleName } = require("./IdHelpers");

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

const validate = createSchemaValidation(
	require("../../schemas/plugins/HashedModuleIdsPlugin.check.js"),
	() => require("../../schemas/plugins/HashedModuleIdsPlugin.json"),
	{
		name: "Hashed Module Ids Plugin",
		baseDataPath: "options"
	}
);

class HashedModuleIdsPlugin {
	/**
	 * @param {HashedModuleIdsPluginOptions=} options options object
	 */
	constructor(options = {}) {
		validate(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;