isTypedArray

Checks whether a value is a TypedArray. This includes all built‑in typed array types such as Uint8Array, Float32Array, and BigInt64Array. You may optionally enforce a specific TypedArray constructor.

This helper never throws and never mutates input.

Signature

function isTypedArray<T extends TypedArray = TypedArray>(
    value: unknown,
    expected?: { new (...args: unknown[]): T },
): value is T

Parameters

Name	Data type	Description
value	unknown	The value to check. Must be a TypedArray to return true.
expected	constructor	Optional. If provided, the value must be an instance of this specific TypedArray type.

Returns

A boolean:

• true: If the value is a TypedArray.
• true: If the value is a TypedArray and matches the expected type.
• false: Otherwise.

Examples

isTypedArray(new Uint8Array())         // true
isTypedArray(new Float32Array())       // true
isTypedArray(new Uint8Array(), Uint8Array) // true
isTypedArray(new Uint8Array(), Float32Array) // false

isTypedArray([])                       // false
isTypedArray(new DataView(...))        // false
isTypedArray(null)                     // false

Notes

• This helper uses ArrayBuffer.isView and excludes DataView, matching the ECMAScript definition of TypedArray.
• It accepts TypedArray subclasses and wrapper objects.
• Use validateTypedArray if you need a Result<T> instead of a boolean.

Next up

isWeakMap