@3m1/service-worker-updater

Manage Create React App's Service Worker update

If you have opted-in for the register callback of serviceWorkerRegistration in the index.js of the PWA version of Create React APP, you probably want to allow your users to update the application once a new service worker has been detected.

How it works

Usually, browsers check for a new service worker version of a PWA every few days, or whenever the user reloads the page. But reloading the page does not necessarily updates the service worker. As the code managing the service worker is usually outside the React components tree, the message of a new service worker detected needs to be passed through another mechanism than props or contexts. Here, we use an event triggered over document, which will previously have been added a listener. The component that adds the listener is inside the React's components tree, and receives and saves the resgistration object for later use in the onLoadNewServiceWorkerAccept callback.

Install

NPM

npm install --save @3m1/service-worker-updater

Yarn

yarn add @3m1/service-worker-updater

Usage

This library is composed by 2 parts:

onServiceWorkerUpdate

Callback to be added to the serviceWorkerRegistration.register call on your index.js. This step is mandatory, or the message will not arrive to your inner component.

import React from 'react'
import ReactDOM from 'react-dom'
import App from './App'
import * as serviceWorkerRegistration from './serviceWorkerRegistration'
import { onServiceWorkerUpdate } from '@3m1/service-worker-updater'

// Render the App
ReactDOM.render(
  <React.StrictMode>
    <App />
  </React.StrictMode>,
  document.getElementById('root')
)

// If you want your app to work offline and load faster, you can change
// unregister() to register() below. Note this comes with some pitfalls.
// Learn more about service workers: https://cra.link/PWA
serviceWorkerRegistration.register({
  onUpdate: onServiceWorkerUpdate
})

// ...

If you are already using the onUpdate callback, you need to add this callback in there:

serviceWorkerRegistration.register({
  onUpdate: (registration) => {
    // Your code goes here
    // ...
    // Then, call this callback:
    onServiceWorkerUpdate(registration)
  }
})

withServiceWorkerUpdater

HOC to wrap a component which will receive 2 extra props:

• newServiceWorkerDetected: boolean indicating if a new version of the service worker has been detected. If true, you should offer the user some way to update the app.
• onLoadNewServiceWorkerAccept: a callback which needs to be called once the user accepts to update to the new Service Worker. You choose what actions needs to be taken by the user to update the service worker (a button, a link, a countdown, ...). During its execution, the page will be reloaded in order to use the newly activated service worker. WARNING! Make sure all unsaved changes are saved before executing it.

import React from 'react'
import {
  withServiceWorkerUpdater,
  ServiceWorkerUpdaterProps
} from '@3m1/service-worker-updater'

const Updater = (props: ServiceWorkerUpdaterProps) => {
  const { newServiceWorkerDetected, onLoadNewServiceWorkerAccept } = props
  return newServiceWorkerDetected ? (
    <>
      New version detected.
      <button onClick={onLoadNewServiceWorkerAccept}>Update!</button>
    </>
  ) : null // If no update is available, render nothing
}

export default withServiceWorkerUpdater(Updater)

For non Typescript projects, use the following snippet:

import React from 'react'
import { withServiceWorkerUpdater } from '@3m1/service-worker-updater'

const Updater = (props) => {
  const { newServiceWorkerDetected, onLoadNewServiceWorkerAccept } = props
  return newServiceWorkerDetected ? (
    <>
      New version detected.
      <button onClick={onLoadNewServiceWorkerAccept}>Update!</button>
    </>
  ) : null // If no update is available, render nothing
}

export default withServiceWorkerUpdater(Updater)

The message sent to the service worker is {type: 'SKIP_WAITING'}, which is the one the PWA version of Create React APP expects in order to launch its self.skipWaiting() method. If you have a different service worker configuration, you can change it here using the second optional argument:

export default withServiceWorkerUpdater(Updater, {
  message: { myCustomType: 'SKIP_WAITING' }
})

Just before reloading the page, 'Controller loaded' will be logged with console.log. If you want to change it, do it so:

export default withServiceWorkerUpdater(Updater, {
  log: () => console.warn('App updated!')
})

Persistence

When a new service worker is detected an event is fired. If the app is refreshed, the event is not fired again so you'll no longer be able to notify users about service worker updates. This package provides a solution to that in the form of a PersistenceService.

The persistence service is injected into the component and handles persisting the state after refresh. The package comes with a default persistence service based on local storage. It can be used thus:

import { LocalStoragePersistenceService } from '@3m1/service-worker-updater'

const Updater = () => {
  /* Your updater component code */
}

export default withServiceWorkerUpdater(Updater, {
  persistenceService: new LocalStoragePersistenceService('myApp')
})

You can define your own persistence layer based on other mechanisms by adhering to the PersistenceService interface:

import { PersistenceService } from '@3m1/service-worker-updater'

class YourPersistenceService implements PersistenceService {
  setUpdateIsNeeded(): void {}

  clear(): void {}

  isUpdateNeeded(): boolean {
    return false
  }
}

:trophy: Thanks to

• Alexander Harding for translating the library into Typescript.

See also

• React Service Worker: A headless React component that wraps around the Navigator Service Worker API to manage your service workers. Inspired by Create React App's service worker registration script.
• Service Worker Updater - React Hook & HOC: This package provides React hook and HOC to check for service worker updates.
• @loopmode/cra-workbox-refresh: Helper for create-react-app v2 apps that use the workbox service worker. Displays a UI that informs the user about updates and recommends a page refresh.

License

GPL-3.0-or-later © github.com/emibcn