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TypedArray.prototype.lastIndexOf()

The lastIndexOf() method of TypedArray instances returns the last index at which a given element can be found in the typed array, or -1 if it is not present. The typed array is searched backwards, starting at fromIndex. This method has the same algorithm as Array.prototype.lastIndexOf().

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Syntax

lastIndexOf(searchElement)
lastIndexOf(searchElement, fromIndex)

Parameters

searchElement: Element to locate in the typed array.
fromIndex Optional: Zero-based index at which to start searching backwards, converted to an integer.

Return value

The last index of searchElement in the typed array; -1 if not found.

Description

See Array.prototype.lastIndexOf() for more details. This method is not generic and can only be called on typed array instances.

Examples

Using lastIndexOf()

const uint8 = new Uint8Array([2, 5, 9, 2]);
uint8.lastIndexOf(2); // 3
uint8.lastIndexOf(7); // -1
uint8.lastIndexOf(2, 3); // 3
uint8.lastIndexOf(2, 2); // 0
uint8.lastIndexOf(2, -2); // 0
uint8.lastIndexOf(2, -1); // 3

Specifications

Specification
ECMAScript Language Specification # sec-%typedarray%.prototype.lastindexof

Browser compatibility

	Desktop						Mobile						Server
	Chrome	Edge	Firefox	Opera	Safari	Chrome Android	Firefox for Android	Opera Android	Safari on IOS	Samsung Internet	WebView Android	Deno	Node.js
`lastIndexOf`	45	12	37 Starting with Firefox 47, this method will no longer return `-0`. For example, `new Uint8Array([0]).lastIndexOf(0, -0)` will now always return `+0`.	32	10	45	37 Starting with Firefox 47, this method will no longer return `-0`. For example, `new Uint8Array([0]).lastIndexOf(0, -0)` will now always return `+0`.	32	10	5.0	45	1.0	4.0.0