TypedArray.prototype.indexOf()
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 indexOf() method of TypedArray instances returns the first index at which a given element can be found in the typed array, or -1 if it is not present. This method has the same algorithm as Array.prototype.indexOf().
Try it
const uint8 = new Uint8Array([10, 20, 30, 40, 50]);
console.log(uint8.indexOf(50));
// Expected output: 4
// From position 3
console.log(uint8.indexOf(20, 3));
// Expected output: -1
console.log(uint8.indexOf(51));
// Expected output: -1
Syntax
js
indexOf(searchElement)
indexOf(searchElement, fromIndex)
Parameters
searchElement-
Element to locate in the typed array.
fromIndexOptional-
Zero-based index at which to start searching, converted to an integer.
Return value
The first index of searchElement in the typed array; -1 if not found.
Description
See Array.prototype.indexOf() for more details. This method is not generic and can only be called on typed array instances.
Examples
Using indexOf()
js
const uint8 = new Uint8Array([2, 5, 9]);
uint8.indexOf(2); // 0
uint8.indexOf(7); // -1
uint8.indexOf(9, 2); // 2
uint8.indexOf(2, -1); // -1
uint8.indexOf(2, -3); // 0
Specifications
| Specification |
|---|
| ECMAScript® 2026 Language Specification # sec-%typedarray%.prototype.indexof |