JAVASCRIPT

Register a service worker

if ('serviceWorker' in navigator) {
  window.addEventListener('load', function() {
    navigator.serviceWorker.register('/sw.js').then(function(registration) {
      // Registration was successful
      console.log('ServiceWorker registration successful with scope: ', registration.scope);
    }, function(err) {
      // registration failed :(
      console.log('ServiceWorker registration failed: ', err);
    });
  });
}

register a service worker

<script>
  if ('serviceWorker' in navigator) {
  window.addEventListener('load', function() {
  navigator.serviceWorker.register('service-worker.js').then(function(registration) {
  // Registration was successful
  console.log('Registered!');
  }, function(err) {
  // registration failed :(
  console.log('ServiceWorker registration failed: ', err);
  }).catch(function(err) {
  console.log(err);
  });
  });
  } else {
  console.log('service worker is not supported');
  }
  </script>

Service Worker registration

// Add the script to your 'index.html' and ...
<script>
  (function() {
    if("serviceWorker" in navigator) {
      navigator.serviceWorker.register("/service-worker.js", {scope: '/'})
        .then(() => console.log("Service Worker registered successfully."))
        .catch(error => console.log("Service Worker registration failed:", error));
    }
  })();
  </script>
// don't forget that works only in 'https://' or 'localhost:port' mode so
// if you don't run any server like express.js then install:
// "webpack-dev-server" from npm and add the following line to your package.json
// "scripts: { "start:dev": "webpack-dev-server" }
//          npm run start:dev
// it will run your app in 'localhost:8080'

register service worker

import { register } from 'register-service-worker'

register('/service-worker.js', {
  registrationOptions: { scope: './' },
  ready (registration) {
    console.log('Service worker is active.')
  },
  registered (registration) {
    console.log('Service worker has been registered.')
  },
  cached (registration) {
    console.log('Content has been cached for offline use.')
  },
  updatefound (registration) {
    console.log('New content is downloading.')
  },
  updated (registration) {
    console.log('New content is available; please refresh.')
  },
  offline () {
    console.log('No internet connection found. App is running in offline mode.')
  },
  error (error) {
    console.error('Error during service worker registration:', error)
  }
})

register service worker

// index.html
window.addEventListener('load', function () {
    navigator
        .serviceWorker
        .register('/service-worker.js');
});