# Convert a Uint8Array to an ArrayBuffer

A [`Uint8Array`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint8Array) is a _typed array_, a view over data in an underlying `ArrayBuffer`. The `buffer` property returns that `ArrayBuffer`.

```ts
const arr = new Uint8Array(64);
arr.buffer; // => ArrayBuffer(64)
```

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The `Uint8Array` may be a view over a _subset_ of the data in the underlying `ArrayBuffer`. In this case, the `buffer` property returns the entire buffer, and the `byteOffset` and `byteLength` properties indicate the subset.

```ts
const arr = new Uint8Array(new ArrayBuffer(64), 16, 32);
arr.buffer; // => ArrayBuffer(64)
arr.byteOffset; // => 16
arr.byteLength; // => 32
```

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See [Binary Data](/runtime/binary-data#conversion).