TypedArray.prototype.lastIndexOf()

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since September 2016.

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

js
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()

js
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

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See also