source: trip-planner-front/node_modules/enhanced-resolve/lib/UnsafeCachePlugin.js

/*
        MIT License http://www.opensource.org/licenses/mit-license.php
        Author Tobias Koppers @sokra
*/

"use strict";

/** @typedef {import("./Resolver")} Resolver */
/** @typedef {import("./Resolver").ResolveRequest} ResolveRequest */
/** @typedef {import("./Resolver").ResolveStepHook} ResolveStepHook */
/** @typedef {{[k: string]: any}} Cache */

function getCacheId(request, withContext) {
        return JSON.stringify({
                context: withContext ? request.context : "",
                path: request.path,
                query: request.query,
                fragment: request.fragment,
                request: request.request
        });
}

module.exports = class UnsafeCachePlugin {
        /**
         * @param {string | ResolveStepHook} source source
         * @param {function(ResolveRequest): boolean} filterPredicate filterPredicate
         * @param {Cache} cache cache
         * @param {boolean} withContext withContext
         * @param {string | ResolveStepHook} target target
         */
        constructor(source, filterPredicate, cache, withContext, target) {
                this.source = source;
                this.filterPredicate = filterPredicate;
                this.withContext = withContext;
                this.cache = cache;
                this.target = target;
        }

        /**
         * @param {Resolver} resolver the resolver
         * @returns {void}
         */
        apply(resolver) {
                const target = resolver.ensureHook(this.target);
                resolver
                        .getHook(this.source)
                        .tapAsync("UnsafeCachePlugin", (request, resolveContext, callback) => {
                                if (!this.filterPredicate(request)) return callback();
                                const cacheId = getCacheId(request, this.withContext);
                                const cacheEntry = this.cache[cacheId];
                                if (cacheEntry) {
                                        return callback(null, cacheEntry);
                                }
                                resolver.doResolve(
                                        target,
                                        request,
                                        null,
                                        resolveContext,
                                        (err, result) => {
                                                if (err) return callback(err);
                                                if (result) return callback(null, (this.cache[cacheId] = result));
                                                callback();
                                        }
                                );
                        });
        }
};