Book Image

Progressive Web Apps with React

By : Scott Domes
Book Image

Progressive Web Apps with React

By: Scott Domes

Overview of this book

For years, the speed and power of web apps has lagged behind native applications. Progressive Web Apps (PWAs) aim to solve this by bridging the gap between the web apps and native apps, delivering a host of exciting features. Simultaneously, React is fast becoming the go-to solution for building modern web UIs, combining ease of development with performance and capability. Using React alongside PWA technology will make it easy for you to build a fast, beautiful, and functional web app. After an introduction and brief overview of the goals of PWAs, the book moves on to setting up the application structure. From there, it covers the Webpack build process and the process of creating React components. You'll learn how to set up the backend database and authentication solution to communicate with Firebase and how to work with React Router. Next, you will create and configure your web app manifest, making your PWA installable on mobile devices. Then you'll get introduced to service workers and see how they work as we configure the app to send push notifications using Firebase Cloud Messaging. We'll also explore the App Shell pattern, a key concept in PWAs and look at its advantages regarding efficient performance. Finally, you'll learn how to add of?ine capabilities to the app with caching and confirm your progress by auditing your PWA with Lighthouse. Also, you'll discover helper libraries and shortcuts that will help you save time and understand the future of PWA development.
Table of Contents (21 chapters)
Title Page
Credits
About the Author
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface

Lazy loading


Lazy loading is the last piece of our PRPL puzzle and is the process of using our application's idle time to load the rest of the JavaScript.

If you yarn deploy our application and navigate to the Network tab in DevTools, you'll see something similar to the following:

We load our main file and then whatever chunk is relevant to the current URL, but then we stop.

We're not loading the other routes during the idle time of our application! We need some way to trigger that loading process as soon as the initial route rendering is done, as soon as the App has mounted.

I think you know where this is going. In the componentDidMount method of App, we simply need to call our three loading methods:

componentDidMount() {
    this.notifications = new NotificationResource(
      firebase.messaging(),
      firebase.database()
    );
    firebase.auth().onAuthStateChanged(user => {
      if (user) {
        this.setState({ user });
        this.listenForMessages();
        this.notifications...