source: trip-planner-front/node_modules/webpack/lib/ids/HashedModuleIdsPlugin.js

/*
        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;