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1# Buffer From
2
3A [ponyfill](https://ponyfill.com) for `Buffer.from`, uses native implementation if available.
4
5## Installation
6
7```sh
8npm install --save buffer-from
9```
10
11## Usage
12
13```js
14const bufferFrom = require('buffer-from')
15
16console.log(bufferFrom([1, 2, 3, 4]))
17//=> <Buffer 01 02 03 04>
18
19const arr = new Uint8Array([1, 2, 3, 4])
20console.log(bufferFrom(arr.buffer, 1, 2))
21//=> <Buffer 02 03>
22
23console.log(bufferFrom('test', 'utf8'))
24//=> <Buffer 74 65 73 74>
25
26const buf = bufferFrom('test')
27console.log(bufferFrom(buf))
28//=> <Buffer 74 65 73 74>
29```
30
31## API
32
33### bufferFrom(array)
34
35- `array` &lt;Array&gt;
36
37Allocates a new `Buffer` using an `array` of octets.
38
39### bufferFrom(arrayBuffer[, byteOffset[, length]])
40
41- `arrayBuffer` &lt;ArrayBuffer&gt; The `.buffer` property of a TypedArray or ArrayBuffer
42- `byteOffset` &lt;Integer&gt; Where to start copying from `arrayBuffer`. **Default:** `0`
43- `length` &lt;Integer&gt; How many bytes to copy from `arrayBuffer`. **Default:** `arrayBuffer.length - byteOffset`
44
45When passed a reference to the `.buffer` property of a TypedArray instance, the
46newly created `Buffer` will share the same allocated memory as the TypedArray.
47
48The optional `byteOffset` and `length` arguments specify a memory range within
49the `arrayBuffer` that will be shared by the `Buffer`.
50
51### bufferFrom(buffer)
52
53- `buffer` &lt;Buffer&gt; An existing `Buffer` to copy data from
54
55Copies the passed `buffer` data onto a new `Buffer` instance.
56
57### bufferFrom(string[, encoding])
58
59- `string` &lt;String&gt; A string to encode.
60- `encoding` &lt;String&gt; The encoding of `string`. **Default:** `'utf8'`
61
62Creates a new `Buffer` containing the given JavaScript string `string`. If
63provided, the `encoding` parameter identifies the character encoding of
64`string`.
65
66## See also
67
68- [buffer-alloc](https://github.com/LinusU/buffer-alloc) A ponyfill for `Buffer.alloc`
69- [buffer-alloc-unsafe](https://github.com/LinusU/buffer-alloc-unsafe) A ponyfill for `Buffer.allocUnsafe`
70