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() Experimental

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

get() Experimental

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

getIds() Experimental

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 an audio file 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,
    },
  );
});