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index.md
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---
title: Uint8Array
slug: Web/JavaScript/Reference/Global_Objects/Uint8Array
page-type: javascript-class
browser-compat: javascript.builtins.Uint8Array
---
{{JSRef}}
The **`Uint8Array`** typed array represents an array of 8-bit unsigned integers. The contents are initialized to `0` unless initialization data is explicitly provided. Once established, you can reference elements in the array using the object's methods, or using standard array index syntax (that is, using bracket notation).
`Uint8Array` is a subclass of the hidden {{jsxref("TypedArray")}} class.
## Constructor
- {{jsxref("Uint8Array/Uint8Array", "Uint8Array()")}}
- : Creates a new `Uint8Array` object.
## Static properties
_Also inherits static properties from its parent {{jsxref("TypedArray")}}_.
- {{jsxref("TypedArray/BYTES_PER_ELEMENT", "Uint8Array.BYTES_PER_ELEMENT")}}
- : Returns a number value of the element size. `1` in the case of `Uint8Array`.
## Static methods
_Inherits static methods from its parent {{jsxref("TypedArray")}}_.
## Instance properties
_Also inherits instance properties from its parent {{jsxref("TypedArray")}}_.
These properties are defined on `Uint8Array.prototype` and shared by all `Uint8Array` instances.
- {{jsxref("TypedArray/BYTES_PER_ELEMENT", "Uint8Array.prototype.BYTES_PER_ELEMENT")}}
- : Returns a number value of the element size. `1` in the case of a `Uint8Array`.
- {{jsxref("Object/constructor", "Uint8Array.prototype.constructor")}}
- : The constructor function that created the instance object. For `Uint8Array` instances, the initial value is the {{jsxref("Uint8Array/Uint8Array", "Uint8Array")}} constructor.
## Instance methods
_Inherits instance methods from its parent {{jsxref("TypedArray")}}_.
## Examples
### Different ways to create a Uint8Array
```js
// From a length
const uint8 = new Uint8Array(2);
uint8[0] = 42;
console.log(uint8[0]); // 42
console.log(uint8.length); // 2
console.log(uint8.BYTES_PER_ELEMENT); // 1
// From an array
const x = new Uint8Array([21, 31]);
console.log(x[1]); // 31
// From another TypedArray
const y = new Uint8Array(x);
console.log(y[0]); // 21
// From an ArrayBuffer
const buffer = new ArrayBuffer(8);
const z = new Uint8Array(buffer, 1, 4);
console.log(z.byteOffset); // 1
// From an iterable
const iterable = (function* () {
yield* [1, 2, 3];
})();
const uint8FromIterable = new Uint8Array(iterable);
console.log(uint8FromIterable);
// Uint8Array [1, 2, 3]
```
## Specifications
{{Specifications}}
## Browser compatibility
{{Compat}}
## See also
- [Polyfill of `Uint8Array` in `core-js`](https://github.com/zloirock/core-js#ecmascript-typed-arrays)
- [JavaScript typed arrays](/en-US/docs/Web/JavaScript/Guide/Typed_arrays) guide
- {{jsxref("TypedArray")}}
- {{jsxref("ArrayBuffer")}}
- {{jsxref("DataView")}}