FetchEvent: FetchEvent() constructor

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since April 2018.

Note: This feature is only available in Service Workers.

The FetchEvent() constructor creates a new FetchEvent object.

Syntax

new FetchEvent(type, options)

A string with the name of the event. It is case-sensitive and browsers always set it to fetch.

An object that, in addition of the properties defined in ExtendableEvent(), can have the following properties:

request: The Request object that would have triggered the event handler.
preloadResponse: A Promise which returns a previously-loaded response to the client.
clientId Optional: The Client that the current service worker is controlling. It defaults to "".
isReload Optional: A boolean value that signifies whether the page was reloaded or not when the event was dispatched. true if yes, and false if not. Typically, pressing the refresh button in a browser is a reload, while clicking a link and pressing the back button is not. If not present, it defaults to false.
replacesClientId Optional: A string which identifies the client which is being replaced by resultingClientId. It defaults to "".
resultingClientId Optional: A string containing the new clientId if the client changes as a result of the page load. It defaults to ""
handled: A pending promise that will be fulfilled once the event has been handled.

A new FetchEvent object.

Specification
Service Workers Nightly # dom-fetchevent-fetchevent

	desktop					mobile
	Chrome	Edge	Firefox	Opera	Safari	Chrome Android	Firefox for Android	Opera Android	Safari on iOS	Samsung Internet	WebView Android	WebView on iOS
`FetchEvent()` constructor	Chrome – Full support Chrome 44 (Release date: 2015-07-21) footnote Full support	Edge – Full support Edge 17 (Release date: 2018-04-30) footnote Full support	Firefox – Full support Firefox 44 (Release date: 2016-01-26) footnote Full support	Opera – Full support Opera 31 (Release date: 2015-08-04) footnote Full support	Safari – Full support Safari 11.1 (Release date: 2018-04-12) footnote Full support	Chrome Android – Full support Chrome Android 44 (Release date: 2015-07-29) footnote Full support	Firefox for Android – Full support Firefox for Android 44 (Release date: 2016-01-26) footnote Full support	Opera Android – Full support Opera Android 32 (Release date: 2015-09-23) footnote Full support	Safari on iOS – Full support Safari on iOS 11.3 (Release date: 2018-03-29) footnote Full support	Samsung Internet – Full support Samsung Internet 4 (Release date: 2016-03-11) footnote Full support	WebView Android – Full support WebView Android 44 (Release date: 2015-07-29) footnote Full support	WebView on iOS – No support WebView on iOS footnote No support

Tip: you can click/tap on a cell for more information.