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javascript instance method

TypedArray.prototype.lastIndexOf()

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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 lastIndexOf().

Interactive exampleOpen the canonical MDN source to run this embedded demo.
const uint8 = new Uint8Array([10, 20, 50, 50, 50, 60]);

console.log(uint8.lastIndexOf(50, 5));
// Expected output: 4

console.log(uint8.lastIndexOf(50, 3));
// Expected output: 3

Syntax

lastIndexOf(searchElement)
lastIndexOf(searchElement, fromIndex)

Parameters

  • searchElement
    • : Element to locate in the typed array.
  • fromIndex Optional

Return value

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

Description

See 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

SpecificationsStandards references are available on the canonical MDN page.

Browser compatibility

Browser compatibilityCompatibility data is available on the canonical MDN page.

See also