/**
 * @license
 * Copyright (c) 2016 The Polymer Project Authors. All rights reserved.
 * This code may only be used under the BSD style license found at
 * http://polymer.github.io/LICENSE.txt
 * The complete set of authors may be found at
 * http://polymer.github.io/AUTHORS.txt
 * The complete set of contributors may be found at
 * http://polymer.github.io/CONTRIBUTORS.txt
 * Code distributed by Google as part of the polymer project is also
 * subject to an additional IP rights grant found at
 * http://polymer.github.io/PATENTS.txt
 */
import { RequestHandler } from 'express';
import * as LRU from 'lru-cache';
export declare const isPolyfill: RegExp;
export declare const babelCompileCache: LRU.Cache<string>;
export declare const getCompileCacheKey: (requestPath: string, body: string, options: {
    compileTarget: string;
    transformModules: boolean;
}) => string;
export declare function babelCompile(compile: 'always' | 'never' | 'auto', moduleResolution: 'none' | 'node', rootDir: string, packageName: string, componentUrl: string, componentDir: string): RequestHandler;