TypedArray.prototype.indexOf()

The indexOf() method of {{jsxref("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 {{jsxref("Array.prototype.indexOf()")}}.

{{InteractiveExample("JavaScript Demo: TypedArray.prototype.indexOf()")}}

```js interactive-example 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-nolint
indexOf(searchElement)
indexOf(searchElement, fromIndex)

Parameters#

• searchElement
• : Element to locate in the typed array.
• fromIndex {{optional_inline}}
• : 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 {{jsxref("Array.prototype.indexOf()")}} for more details. This method is not generic and can only be called on typed array instances.

Examples#

Using indexOf()#

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#

{{Specifications}}

Browser compatibility#

{{Compat}}

See also#

• Polyfill of TypedArray.prototype.indexOf in core-js
• JavaScript typed arrays guide
• {{jsxref("TypedArray")}}
• {{jsxref("TypedArray.prototype.findIndex()")}}
• {{jsxref("TypedArray.prototype.findLastIndex()")}}
• {{jsxref("TypedArray.prototype.lastIndexOf()")}}
• {{jsxref("Array.prototype.indexOf()")}}
• {{jsxref("String.prototype.indexOf()")}}