/**
 * @license
 * Copyright 2017 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/**
 * Returns navigator.userAgent string or '' if it's not defined.
 * @return {string} user agent string
 */
export declare const getUA: () => string;
/**
 * Detect Cordova / PhoneGap / Ionic frameworks on a mobile device.
 *
 * Deliberately does not rely on checking `file://` URLs (as this fails PhoneGap in the Ripple emulator) nor
 * Cordova `onDeviceReady`, which would normally wait for a callback.
 *
 * @return {boolean} isMobileCordova
 */
export declare const isMobileCordova: () => boolean;
/**
 * Detect React Native.
 *
 * @return {boolean} True if ReactNative environment is detected.
 */
export declare const isReactNative: () => boolean;
/**
 * Detect Node.js.
 *
 * @return {boolean} True if Node.js environment is detected.
 */
export declare const isNodeSdk: () => boolean;