# Update strategies — Progressive Web Apps

Source: https://www.geekswithgeeks.com/en/pwa/pwa-update-strategies

> Implement strategies to update service workers and cached content without breaking user experience.

## Update patterns

When service workers or cache changes, you need strategies to safely update without breaking ongoing operations. Patterns include checking for updates, skipping waiting, and notifying users.

## Detect and update service worker

Check for updates periodically and notify users when a new version is available.

```javascript
navigator.serviceWorker.getRegistration().then(reg => {
  setInterval(() => {
    reg.update(); // Check for updates
  }, 60000); // Every minute
});

let newWorker;
navigator.serviceWorker.addEventListener('controllerchange', () => {
  console.log('New service worker controlling the page');
  // Notify user to refresh
});

navigator.serviceWorker.onmessage = event => {
  if (event.data.type === 'SKIP_WAITING') {
    newWorker?.postMessage({ type: 'CLIENTS_CLAIM' });
  }
};
```

Output:

```
App checks for service worker updates and notifies users of new versions.
```

## A common trap

Do not force immediate updates without notifying users. Let users decide when to refresh their app.