webpack/lib/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 createHash = require("./util/createHash");

const validateOptions = require("schema-utils");
const schema = require("../schemas/plugins/HashedModuleIdsPlugin.json");

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

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

		validateOptions(schema, options, "Hashed Module Ids Plugin");

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

	apply(compiler) {
		const options = this.options;
		compiler.hooks.compilation.tap("HashedModuleIdsPlugin", compilation => {
			const usedIds = new Set();
			compilation.hooks.beforeModuleIds.tap(
				"HashedModuleIdsPlugin",
				modules => {
					for (const module of modules) {
						if (module.id === null && module.libIdent) {
							const id = module.libIdent({
								context: this.options.context || compiler.options.context
							});
							const hash = createHash(options.hashFunction);
							hash.update(id);
							const hashId = /** @type {string} */ (hash.digest(
								options.hashDigest
							));
							let len = options.hashDigestLength;
							while (usedIds.has(hashId.substr(0, len))) len++;
							module.id = hashId.substr(0, len);
							usedIds.add(module.id);
						}
					}
				}
			);
		});
	}
}

module.exports = HashedModuleIdsPlugin;