source: trip-planner-front/node_modules/enhanced-resolve/lib/FileExistsPlugin.js@ e29cc2e

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

"use strict";

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

module.exports = class FileExistsPlugin {
        /**
         * @param {string | ResolveStepHook} source source
         * @param {string | ResolveStepHook} target target
         */
        constructor(source, target) {
                this.source = source;
                this.target = target;
        }

        /**
         * @param {Resolver} resolver the resolver
         * @returns {void}
         */
        apply(resolver) {
                const target = resolver.ensureHook(this.target);
                const fs = resolver.fileSystem;
                resolver
                        .getHook(this.source)
                        .tapAsync("FileExistsPlugin", (request, resolveContext, callback) => {
                                const file = request.path;
                                if (!file) return callback();
                                fs.stat(file, (err, stat) => {
                                        if (err || !stat) {
                                                if (resolveContext.missingDependencies)
                                                        resolveContext.missingDependencies.add(file);
                                                if (resolveContext.log) resolveContext.log(file + " doesn't exist");
                                                return callback();
                                        }
                                        if (!stat.isFile()) {
                                                if (resolveContext.missingDependencies)
                                                        resolveContext.missingDependencies.add(file);
                                                if (resolveContext.log) resolveContext.log(file + " is not a file");
                                                return callback();
                                        }
                                        if (resolveContext.fileDependencies)
                                                resolveContext.fileDependencies.add(file);
                                        resolver.doResolve(
                                                target,
                                                request,
                                                "existing file: " + file,
                                                resolveContext,
                                                callback
                                        );
                                });
                        });
        }
};