If you have known beforehand that you want your react-app to be a PWA(Progressive Web App) you could have used the create-react template pwa like so :
npx create-react-app my-app --template pwa
But you didn't😁So here we are.
In this article, I will show you how to turn your react app into a PWA.
Let's go 🚀
1. Add workbox dependencies
workbox is a library that helps you to deal with service workers.
Add the following into your package.json file
...
"dependencies": {
...
"workbox-background-sync": "^5.1.3",
"workbox-broadcast-update": "^5.1.3",
"workbox-cacheable-response": "^5.1.3",
"workbox-core": "^5.1.3",
"workbox-expiration": "^5.1.3",
"workbox-google-analytics": "^5.1.3",
"workbox-navigation-preload": "^5.1.3",
"workbox-precaching": "^5.1.3",
"workbox-range-requests": "^5.1.3",
"workbox-routing": "^5.1.3",
"workbox-strategies": "^5.1.3",
"workbox-streams": "^5.1.3"
},
...
install the packages using your favourite package manager by typing this on your terminal and pressing enter
npm / yarn install
2. create src/serviceWorkerRegistration.js
Copy and paste the following to the file
const isLocalhost = Boolean(
window.location.hostname === 'localhost' ||
window.location.hostname === '[::1]' ||
window.location.hostname.match(/^127(?:\.(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)){3}$/)
);
export function register(config) {
if (process.env.NODE_ENV === 'production' && 'serviceWorker' in navigator) {
const publicUrl = new URL(process.env.PUBLIC_URL, window.location.href);
if (publicUrl.origin !== window.location.origin) {
return;
}
window.addEventListener('load', () => {
const swUrl = `${process.env.PUBLIC_URL}/service-worker.js`;
if (isLocalhost) {
checkValidServiceWorker(swUrl, config);
navigator.serviceWorker.ready.then(() => {
console.log(
'This web app is being served cache-first by a service ' +
'worker. To learn more, visit https://cra.link/PWA'
);
});
} else {
registerValidSW(swUrl, config);
}
});
}
}
function registerValidSW(swUrl, config) {
navigator.serviceWorker
.register(swUrl)
.then((registration) => {
registration.onupdatefound = () => {
const installingWorker = registration.installing;
if (installingWorker == null) {
return;
}
installingWorker.onstatechange = () => {
if (installingWorker.state === 'installed') {
if (navigator.serviceWorker.controller) {
console.log(
'New content is available and will be used when all ' +
'tabs for this page are closed. See https://cra.link/PWA.'
);
if (config && config.onUpdate) {
config.onUpdate(registration);
}
} else {
console.log('Content is cached for offline use.');
if (config && config.onSuccess) {
config.onSuccess(registration);
}
}
}
};
};
})
.catch((error) => {
console.error('Error during service worker registration:', error);
});
}
function checkValidServiceWorker(swUrl, config) {
fetch(swUrl, {
headers: { 'Service-Worker': 'script' },
})
.then((response) => {
const contentType = response.headers.get('content-type');
if (
response.status === 404 ||
(contentType != null && contentType.indexOf('javascript') === -1)
) {
navigator.serviceWorker.ready.then((registration) => {
registration.unregister().then(() => {
window.location.reload();
});
});
} else {
registerValidSW(swUrl, config);
}
})
.catch(() => {
console.log('No internet connection found. App is running in offline mode.');
});
}
export function unregister() {
if ('serviceWorker' in navigator) {
navigator.serviceWorker.ready
.then((registration) => {
registration.unregister();
})
.catch((error) => {
console.error(error.message);
});
}
}
3. create src/service-worker.js
copy and paste the following
import { clientsClaim } from 'workbox-core';
import { ExpirationPlugin } from 'workbox-expiration';
import { precacheAndRoute, createHandlerBoundToURL } from 'workbox-precaching';
import { registerRoute } from 'workbox-routing';
import { StaleWhileRevalidate } from 'workbox-strategies';
clientsClaim();
precacheAndRoute(self.__WB_MANIFEST);
const fileExtensionRegexp = new RegExp('/[^/?]+\\.[^/]+$');
registerRoute(
({ request, url }) => {
if (request.mode !== 'navigate') {
return false;
}
if (url.pathname.startsWith('/_')) {
return false;
}
if (url.pathname.match(fileExtensionRegexp)) {
return false;
}
return true;
},
createHandlerBoundToURL(process.env.PUBLIC_URL + '/index.html')
);
registerRoute(
({ url }) => url.origin === self.location.origin && url.pathname.endsWith('.png'),
new StaleWhileRevalidate({
cacheName: 'images',
plugins: [
new ExpirationPlugin({ maxEntries: 50 }),
],
})
);
self.addEventListener('message', (event) => {
if (event.data && event.data.type === 'SKIP_WAITING') {
self.skipWaiting();
}
});
4. Register the service worker on src/index.js
...
import * as serviceWorkerRegistration from './serviceWorkerRegistration';
ReactDOM.render(
<React.StrictMode>
<App />
</React.StrictMode>,
document.getElementById('root')
);
serviceWorkerRegistration.register();
That's all you need to do. Now for
Testing
if it actually worked. Which I bet you it did.
Here is a screenshot of the service worker being detected by chrome devTools.
to view this first build your app by running
npm / yarn build
and serve it by:
serve -s build
that's if you have serve already installed.
and open up devTools ( ctrl + shift + I ) -> Applications -> Service Workers
Conclusion
You manually turned your react-app into a PWA by registering a service worker.🎉
Questions or suggestions? Let me know in the comments.
