source: imaps-frontend/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 {import("./Resolver").ResolveContextYield} ResolveContextYield */
/** @typedef {{[k: string]: ResolveRequest | ResolveRequest[] | undefined}} Cache */

/**
 * @param {string} type type of cache
 * @param {ResolveRequest} request request
 * @param {boolean} withContext cache with context?
 * @returns {string} cache id
 */
function getCacheId(type, request, withContext) {
        return JSON.stringify({
                type,
                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 isYield = typeof resolveContext.yield === "function";
                                const cacheId = getCacheId(
                                        isYield ? "yield" : "default",
                                        request,
                                        this.withContext
                                );
                                const cacheEntry = this.cache[cacheId];
                                if (cacheEntry) {
                                        if (isYield) {
                                                const yield_ = /** @type {Function} */ (resolveContext.yield);
                                                if (Array.isArray(cacheEntry)) {
                                                        for (const result of cacheEntry) yield_(result);
                                                } else {
                                                        yield_(cacheEntry);
                                                }
                                                return callback(null, null);
                                        }
                                        return callback(null, /** @type {ResolveRequest} */ (cacheEntry));
                                }

                                /** @type {ResolveContextYield|undefined} */
                                let yieldFn;
                                /** @type {ResolveContextYield|undefined} */
                                let yield_;
                                /** @type {ResolveRequest[]} */
                                const yieldResult = [];
                                if (isYield) {
                                        yieldFn = resolveContext.yield;
                                        yield_ = result => {
                                                yieldResult.push(result);
                                        };
                                }

                                resolver.doResolve(
                                        target,
                                        request,
                                        null,
                                        yield_ ? { ...resolveContext, yield: yield_ } : resolveContext,
                                        (err, result) => {
                                                if (err) return callback(err);
                                                if (isYield) {
                                                        if (result) yieldResult.push(result);
                                                        for (const result of yieldResult) {
                                                                /** @type {ResolveContextYield} */
                                                                (yieldFn)(result);
                                                        }
                                                        this.cache[cacheId] = yieldResult;
                                                        return callback(null, null);
                                                }
                                                if (result) return callback(null, (this.cache[cacheId] = result));
                                                callback();
                                        }
                                );
                        });
        }
};