source: imaps-frontend/node_modules/enhanced-resolve/lib/DescriptionFilePlugin.js

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

"use strict";

const DescriptionFileUtils = require("./DescriptionFileUtils");

/** @typedef {import("./Resolver")} Resolver */
/** @typedef {import("./Resolver").ResolveRequest} ResolveRequest */
/** @typedef {import("./Resolver").ResolveStepHook} ResolveStepHook */

module.exports = class DescriptionFilePlugin {
        /**
         * @param {string | ResolveStepHook} source source
         * @param {string[]} filenames filenames
         * @param {boolean} pathIsFile pathIsFile
         * @param {string | ResolveStepHook} target target
         */
        constructor(source, filenames, pathIsFile, target) {
                this.source = source;
                this.filenames = filenames;
                this.pathIsFile = pathIsFile;
                this.target = target;
        }

        /**
         * @param {Resolver} resolver the resolver
         * @returns {void}
         */
        apply(resolver) {
                const target = resolver.ensureHook(this.target);
                resolver
                        .getHook(this.source)
                        .tapAsync(
                                "DescriptionFilePlugin",
                                (request, resolveContext, callback) => {
                                        const path = request.path;
                                        if (!path) return callback();
                                        const directory = this.pathIsFile
                                                ? DescriptionFileUtils.cdUp(path)
                                                : path;
                                        if (!directory) return callback();
                                        DescriptionFileUtils.loadDescriptionFile(
                                                resolver,
                                                directory,
                                                this.filenames,
                                                request.descriptionFilePath
                                                        ? {
                                                                        path: request.descriptionFilePath,
                                                                        content: request.descriptionFileData,
                                                                        directory: /** @type {string} */ (request.descriptionFileRoot)
                                                          }
                                                        : undefined,
                                                resolveContext,
                                                (err, result) => {
                                                        if (err) return callback(err);
                                                        if (!result) {
                                                                if (resolveContext.log)
                                                                        resolveContext.log(
                                                                                `No description file found in ${directory} or above`
                                                                        );
                                                                return callback();
                                                        }
                                                        const relativePath =
                                                                "." + path.slice(result.directory.length).replace(/\\/g, "/");
                                                        /** @type {ResolveRequest} */
                                                        const obj = {
                                                                ...request,
                                                                descriptionFilePath: result.path,
                                                                descriptionFileData: result.content,
                                                                descriptionFileRoot: result.directory,
                                                                relativePath: relativePath
                                                        };
                                                        resolver.doResolve(
                                                                target,
                                                                obj,
                                                                "using description file: " +
                                                                        result.path +
                                                                        " (relative path: " +
                                                                        relativePath +
                                                                        ")",
                                                                resolveContext,
                                                                (err, result) => {
                                                                        if (err) return callback(err);

                                                                        // Don't allow other processing
                                                                        if (result === undefined) return callback(null, null);
                                                                        callback(null, result);
                                                                }
                                                        );
                                                }
                                        );
                                }
                        );
        }
};