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service-worker

Custom Element for declaratively adding a service worker with optional auto-update.

Example

``html
path="./service-worker.js"
scope="/muh-data/"
auto-reload
>
`

Properties

| Property | Attribute | Type | Default | Description |
|-----------------|-----------------|-------------------------|----------------------|--------------------------------------------------|
| autoReload | auto-reload | boolean | false | If true, when updates are found, the page will automatically
reload, so long as the user has not yet interacted with it. |
| channelName | channel-name | string \| null | "service-worker" | Channel name for communicating with the service worker. |
| error | error | Error | | Error state of the service-worker registration |
| installed | installed | boolean | false | True when the service worker is installed. |
| path | path | string | "/service-worker.js" | Path to the service worker script. |
| scope | scope | string | "/" | Scope for the service worker. |
| serviceWorker | | ServiceWorker \| null | null | A reference to the service worker instance. |
| updateAction | update-action | string \| null | "skipWaiting" | String passed to serviceWorker which triggers self.skipWaiting().
String will be passed in message.action. |

Methods

| Method | Type | Description |
|-------------------------|--------------------------------------------------|--------------------------------------------------|
| #onError | (error: Error): Error | Sets the error property |
| #onRegistration | (reg: ServiceWorkerRegistration): ServiceWorkerRegistration | |
| #refresh | (): void | |
| #track | (serviceWorker: ServiceWorker): ServiceWorker | Listen for changes on a new worker, notify when installed. 🍞 |
| #update | (serviceWorker: ServiceWorker): ServiceWorker | When an update is found, if user has not yet interacted with the page,
reload it for them, otherwise, prompt them to reload 🍩. |
| #updateChannelName | (): void | |
| #updateConfig | (): void | |
| registerServiceWorker | (options?: Partial> \| undefined): Promise | Registers a service worker, and prompts to update as needed |

Events

| Event | Type | Description |
|-----------|-----------------------------|--------------------------------------------------|
| change | ServiceWorkerChangeEvent | When the service worker changes |
| error | ServiceWorkerErrorEvent | When an error occurs |
| message | ServiceWorkerMessageEvent | When a message is received on the broadcast channel |

Updating the Service Worker.

When an updated service worker is detected, will post a message to the service worker with the contents { action: this.updateAction }. You can customize the name of the passed action by setting the updateAction property or the update-action attribute (they will sync with each other). updateAction is by 'skipWaiting' by default. You can then handle that message in your service worker by running self.skipWaiting():

`js
self.addEventListener('message', event => {
switch (event.data.action) {
case 'skipWaiting': return self.skipWaiting();
}
});
`

If auto-reload is set, will check if the user has not yet interacted with the app, and if she hasn't, refresh the page by calling location.reload() when the new service-worker is installed. Listen for the service-worker-changed event to display a message to the user when the service worker updates.

`js
const dialogTemplate = document.createElement('template');
dialogTemplate.innerHTML =

New Version Available!

Reload the Page?

OK
Cancel

;
document.querySelector('service-worker')
.addEventListener('service-worker-changed', event => {
const dialog = dialogTemplate.content.cloneNode(true);
dialog.addEventListener('close', function({ returnValue }) {
if (returnValue === 'confirm') location.reload();
});
document.body.append(dialog);
dialog.showModal();
})
`

$3

If you are using sw-precache to generate your SW, it will automatically skip waiting on reload, unless you specify otherwise in sw-precache-config.js

$3

Workbox offers a similar feature, although you must opt in when constructing the workbox instance.

#### Directly in service-worker.js

`js
// service-worker.js
const workboxSW = new WorkboxSW({
skipWaiting: true,
});
`

#### Workbox CLI
`js
// workbox-config.js
module.exports = {
// ...
skipWaiting: true,
};
`

#### Rollup
`js
// rollup.config.js
import { generateSW } from 'rollup-plugin-workbox';
export default {
// ...
// use workbox-config.js as above
plugins: [generateSW(require('./workbox-config.js'))]
}
`

#### Webpack
`js
// webpack.config.js
const workboxPlugin = require('workbox-webpack-plugin');

plugins: [
new workboxPlugin({
skipWaiting: true,
}),
];
`

#### Gulp
`js
// gulpfile.js
const workbox = require('workbox-build');

gulp.task('generate-service-worker', () => {
workbox.generateSW({
skipWaiting: true,
});
});
``