text: /*
   * @license
   * Your First PWA Codelab (https://g.co/codelabs/pwa)
   * Copyright 2019 Google Inc. All rights reserved.
   *
   * 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
   *
   *     https://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
   */
  'use strict';
  
  let deferredInstallPrompt = null;
  const installButton = document.getElementById('butInstall');
  installButton.addEventListener('click', installPWA);
  
  // CODELAB: Add event listener for beforeinstallprompt event
  window.addEventListener('beforeinstallprompt', saveBeforeInstallPromptEvent);
  
  /**
   * Event handler for beforeinstallprompt event.
   *   Saves the event & shows install button.
   *
   * @param {Event} evt
   */
  function saveBeforeInstallPromptEvent(evt) {
    // CODELAB: Add code to save event & show the install button.
  deferredInstallPrompt = evt;
  installButton.removeAttribute('hidden');
  }
  
  
  /**
   * Event handler for butInstall - Does the PWA installation.
   *
   * @param {Event} evt
   */
  function installPWA(evt) {
    // CODELAB: Add code show install prompt & hide the install button.
  deferredInstallPrompt.prompt();
  // Hide the install button, it can't be called twice.
    evt.srcElement.setAttribute('hidden', true);
    // CODELAB: Log user response to prompt.
  deferredInstallPrompt.userChoice
      .then((choice) => {
        if (choice.outcome === 'accepted') {
          console.log('User accepted the A2HS prompt', choice);
        } else {
          console.log('User dismissed the A2HS prompt', choice);
        }
        deferredInstallPrompt = null;
      });
  }
  
  // CODELAB: Add event listener for appinstalled event
  window.addEventListener('appinstalled', logAppInstalled);
  /**
   * Event handler for appinstalled event.
   *   Log the installation to analytics or save the event somehow.
   *
   * @param {Event} evt
   */
  function logAppInstalled(evt) {
    // CODELAB: Add code to log the event
  console.log('Weather App was installed.', evt);
  }