TheupdateUI() method of theBackgroundFetchUpdateUIEvent 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

optionsOptional

An object containing any of the following:

iconsOptional

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.

sizesOptional

A string which is equivalent to thesizes attribute of the<link> element.

typeOptional

A string containing an image MIME type.

labelOptional

A string providing a name for the associated image.

titleOptional

A string containing the new title of the user interface.

Return value

APromise.

Exceptions

InvalidStateErrorDOMException

Thrown if any of the following are true:

• TheisTrusted property isfalse.
• TheBackgroundFetchUpdateUIEvent UI updated flag is already set, indicating that theupdateUI() method has already been called.
• TheBackgroundFetchUpdateUIEvent 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