Web/API/XRInputSourceArray/length

Secure contextThis feature is available only in secure contexts (HTTPS), in some or all supporting browsers.

The read-only length property returns an integer value indicating the number of items in the input source list represented by the XRInputSourceArray object.

Syntax

let inputSourceCount = xrInputSourceArray.length;

Value

An integer value indicating the number of XRInputSource objects representing WebXR input sources are includled in the array.

Examples

In this example, a game that requires at least one input source uses length to check this before proceeding to allow the user to play the game.

let sources = xrSession.inputSources;

if (sources.length === 0) {
  showAlertDialog("You need to have at least one controller to play Super Duper Shark Jump Fest 9000.",
                  [
                    { label: "Shop Now", url: "https://www.amazon.com/s?k=vr+controllers" },
                    { label: "Quit" handler: quitGame }
                  ]);
}

Here, if length is 0, a hypothetical showAlertDialog() function is called with a prompt string explaining the need for a controller, and an array of objects, each describing a button and what should happen when it's clicked. The first takes the user to an Amazon.com search for VR controllers, and the second calls a quitGame() function to start shutting the game program down.

Specifications

Specification	Status	Comment
WebXR Device APIThe definition of 'XRInputSourceArray.length' in that specification.	Working Draft	Initial definition.

Browser compatibility

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`length`	Chrome Full support 79	Edge Full support 79	Firefox No support No	IE No support No	Opera No support No	Safari No support No	WebView Android No support No	Chrome Android Full support 79	Firefox Android No support No	Opera Android No support No	Safari iOS No support No	Samsung Internet Android Full support 11.2

Legend

Full support: Full support
No support: No support

XRInputSourceArray.length by Mozilla Contributors is licensed under CC-BY-SA 2.5.