PWA react apps (Progressive web apps) are web apps that use modern web capabilities to deliver native-like experiences. With features like offline support, home screen installation, and push notifications, PWAs combine the best of web and mobile apps. spotify is an example of progressive web app.

In this guide, we’ll walk through building a PWA React app. We’ll use React hooks and functional components to create a fast, lightweight app. We’ll cover concepts like service workers, manifest files, and caching strategies to make our PWA React app reliable and installable.

By the end, you’ll have a solid understanding of what goes into building a production-ready PWA React app. Whether you’re looking to boost engagement for an existing web app or build one from scratch, let’s dive in!

Prerequisites

Before we start building a PWA React app, make sure you have Node.js and the React CLI tools installed. We’ll also use Workbox for handling service workers.

To install it:

npm install workbox-build --save-dev

With that out of the way, let’s get coding!

Setting Up the React App

We’ll use Create React App to quickly scaffold a React project:

npx create-react-app my-pwa

This sets up everything we need, like webpack, Babel, and testing utilities.

Next, we’ll want to clean up the default boilerplate code:

  • Delete any unused files like logo.svg
  • Remove boilerplate CSS
  • Clear out the App.js and index.js files

Our blank canvas React app is ready! Now we can focus on adding PWA functionality.

Registering a Service Worker

A service worker is the main requirement for turning our web app into a PWA. It’s a script that runs separately from the main browser thread, enabling features like push notifications, background syncing, and offline support.

We’ll use Workbox to generate the service worker for us.

First, create a file workbox-config.js with:

module.exports = {
  "globDirectory": "build/",
  "globPatterns": [
    "**/*.{js,css,html,png}"
  ],
  "swDest": "build/service-worker.js" 
};

This tells Workbox to precache all our key files from the build folder.

Next, update the build script in package.json:

"build": "react-scripts build && workbox generateSW workbox-config.js"

Now when we build, it will generate the production assets as well as the service worker file.

The last step is registering the service worker in index.js:

import {registerRoute} from 'workbox-routing';

if ('serviceWorker' in navigator) {
  window.addEventListener('load', () => {
    navigator.serviceWorker.register('/service-worker.js'); 
  });
}

And we’ve implemented offline support with just a few lines of code!

Creating the App Manifest

For our PWA React app to seem like a native app when installed to the home screen, we need an app manifest. This is a JSON file that defines how the app appears.

In the public folder, create manifest.json:

{
  "short_name": "My PWA",
  "name": "My React Progressive Web App",
  "icons": [
    {
      "src": "icon-192x192.png",
      "type": "image/png", 
      "sizes": "192x192"
    }
  ],
  "start_url": "/", 
  "background_color": "#3367D6",
  "display": "standalone",
  "scope": "/", 
  "theme_color": "#3367D6" 
}

This defines the app name, icon, colors, and more. Be sure to add your 192×192 png icon file as well.

Then in index.html, link to it:

<link rel="manifest" href="%PUBLIC_URL%/manifest.json">

Perfect! Our PWA React app now knows how to configure itself when installed to the home screen.

Implementing Offline Functionality

We already have offline support handled by our service worker generated from Workbox. But how do we deal with cached data?

Say we were building a weather app that makes an API call to fetch the user’s location and weather:

import { useState, useEffect } from 'react';

function App() {
  const [weather, setWeather] = useState(null);

  useEffect(() => {
    navigator.geolocation.getCurrentPosition((position) => {

      fetchWeather(position);

    });
  }, []);

  const fetchWeather = async (position) => { 
    // Fetch weather data 
  }

  if (!weather) {
    return <p>Loading...</p>;
  }

  return ( 
    // UI Components
  );
}

This works well online. But offline, the API call would fail.

So we need to update fetchWeather to handle offline caching:

const fetchWeather = async (position) => {

  // Fetch data from cache first

  // Make API call 

  // Store response in cache

}

Here we check if we have cached weather data first, before making the API call. If the API is down, we can show the last fetched weather data from the cache. And when we do fetch new data, we also update the cache.

This pattern works great for handling offline functionality in React PWAs!

Summary

And that covers the key elements for building a progressive web app with React! Here are a few takeaways:

  • Service workers enable powerful features like offline caching, background syncing, push notifications
  • App manifests allow web apps to be installed to the home screen like native apps
  • Handling offline data with caches creates a seamless experience
  • React hooks help build fast, modular PWAs

By leveraging modern browser capabilities with React’s flexible architecture, you can build web apps that feel like high-quality native experiences. Users enjoy extra convenience and reliability.

Ready to Develop Your Next PWA React app?

PWAs unlock game-changing opportunities for user engagement. Users spend more time in apps that offer consistency – whether online or offline.

With over a decade of experience building and deploying web applications, I have delivered successful PWAs for companies big and small. From prototyping concepts to full-scale deployment, I provide end-to-end PWA development services as a freelance developer.