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

Welcome to ReactDOM


Here's a secret about React--it's a library for creating UIs, but not a library for rendering UIs. In itself, it has no mechanism for rendering a UI to the browser.

Fortunately, the creators of React also have a package called ReactDOM for exactly this purpose. Let's install it and then see how it works.

First, we install it with yarn add [email protected].

Then, require it in index.html in much the same way as React:

<body>
  <img src="assets/icon.png" id="test-image"/>
  <h1>Hello world!</h1>
  <div id="root"></div>
  <script src="../node_modules/react/dist/react.js"></script>
  <script src="../node_modules/react-dom/dist/react-dom.js"></script>
  <script>
    console.log(React.createElement('h1', null, 'Hello from react!'));
  </script>
</body&gt;

ReactDOM has a function called render, which takes two arguments: the React element to be rendered to the screen (hey, we have that already!), and the HTML element it will be rendered inside.

So, we have the first argument, but not the second. We need something in our existing HTML we can grab and hook into; ReactDOM will inject our React element inside of it.

So, below our existing <h1> tag, create an empty div with the ID root.

Then, in our ReactDOM.render function, we’ll pass in the React element, and then use document.getElementById to grab our new div.

Here's what our index.html should look like:

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <meta charset="utf-8">
    <link rel="stylesheet" href="assets/app.css">
    <link rel="shortcut icon" href="assets/favicon.ico" type="image/x-icon">
  </head>
  <body>
    <img src="assets/icon.png" id="test-image"/>
    <h1>Hello world!</h1>
    <div id="root"></div>
    <script src="../node_modules/react/dist/react.js"></script>
    <script src="../node_modules/react-dom/dist/react-dom.js"></script>
    <script>
ReactDOM.render(React.createElement('h1', null, 'Hello from react!'), 
      document.getElementById('root'));
    </script>
  </body>
</html>

Reload the page, and you should see 'Hello from React!' text in the middle of the screen!