The BackgroundFetchManager interface of the Background Fetch API is a map where the keys are background fetch IDs and the values are BackgroundFetchRegistration objects.

None.

fetch()

Returns a Promise that resolves with a BackgroundFetchRegistration object for a supplied array of URLs and Request objects.

get()

Returns a Promise that resolves with the BackgroundFetchRegistration associated with the provided id or undefined if the id is not found.

getIDs()

Returns the IDs of all registered background fetches.

The example below shows how to get an instance of BackgroundFetchManager from a ServiceWorkerRegistration object and calls fetch() to download a video in the background.

navigator.serviceWorker.ready.then(async (swReg) => {
  const bgFetch = await swReg.backgroundFetch.fetch('my-fetch', ['/ep-5.mp3', 'ep-5-artwork.jpg'], {
    title: 'Episode 5: Interesting things.',
    icons: [{
      sizes: '300x300',
      src: '/ep-5-icon.png',
      type: 'image/png',
    }],
    downloadTotal: 60 * 1024 * 1024,
  });
});