[PWA] sw-precache

Link to CodeLab

 In this codelab, we'll retrace those steps but this time we'll use a tool called sw-precache to add offline functionality with only six lines of code. It's never been easier to add service worker support to an existing app, and we'll show you how in this codelab.

Learning:

• What the sw-precache tool is and how it can help you be more productive

• How to add a basic service worker to an existing project using sw-precache

Install:

git clone https://github.com/GoogleChrome/airhorn.git

cd airhorn
git checkout code-lab
npm install
npm install --save-dev sw-precache
cd app
python -m SimpleHTTPServer 3000

Gulp:

// Generate sw.js
gulp.task('generate-service-worker', function(callback) {
  var path = require('path');
  var swPrecache = require('sw-precache');
  var rootDir = 'app';

  swPrecache.write(path.join(rootDir, 'sw.js'), {
    staticFileGlobs: [rootDir + '/**/*.{js,html,css,png,jpg,gif,mp3}'],
    stripPrefix: rootDir
  }, callback);
});

Run:

gulp generate-service-worker

Then in app folder, you should see sw.js file generated.

HTML: inisde index.html:

            <script>
                  if ('serviceWorker' in navigator) {
                        navigator.serviceWorker.register('/sw.js').then(function() {
                              console.log("Service Worker Registered");
                        });
                  }
            </script>

Verify Your App:

cd app
python -m SimpleHTTPServer 3000

Open chrome://serviceworker-internals/ in Chrome. This will show you a list of all the registered service workers, which you can use to verify your service worker has indeed properly registered.

Kill the serve and reload the page, everything should work as the same.