BackgroundFetchUpdateUIEvent: updateUI() method

Limited availabilityAvailable in workers

The updateUI() method of the BackgroundFetchUpdateUIEvent interface updates the title and icon in the user interface to show the status of a background fetch.

This method may only be run once, to notify the user on a failed or a successful fetch.

Syntax

updateUI()
updateUI(options)

Parameters

• options Optional
  • : An object containing any of the following:

    • icons Optional

      • : A list of one or more image resources, containing icons for use in the user interface. An image resource is an object containing:
        • src
          • : A string which is a URL of an image.
        • sizes Optional
          • : A string which is equivalent to the sizes attribute of the <link> element.
        • type Optional
          • : A string containing an image MIME type.
        • label Optional
          • : A string providing a name for the associated image.

    • title Optional

      • : A string containing the new title of the user interface.

Return value

A Promise.

Exceptions

• InvalidStateError DOMException
  • : Thrown if any of the following are true:
    • The isTrusted property is false.
    • The BackgroundFetchUpdateUIEvent UI updated flag is already set, indicating that the updateUI() method has already been called.
    • The BackgroundFetchUpdateUIEvent is not active.

Examples

The following example demonstrates updating the UI with a title and image icon on a successful fetch.

addEventListener("backgroundfetchsuccess", (event) => {
  event.updateUI({
    title: "Episode 5 ready to listen!",
    icon: {
      src: "path/to/success.ico",
      sizes: "16x16 32x32 64x64",
    },
  });
});

Specifications

Browser compatibility