Current File : //lib/node_modules/npm/node_modules/buffer-from/readme.md
# Buffer From
A [ponyfill](https://ponyfill.com) for `Buffer.from`, uses native implementation if available.
## Installation
```sh
npm install --save buffer-from
```
## Usage
```js
const bufferFrom = require('buffer-from')
console.log(bufferFrom([1, 2, 3, 4]))
//=> <Buffer 01 02 03 04>
const arr = new Uint8Array([1, 2, 3, 4])
console.log(bufferFrom(arr.buffer, 1, 2))
//=> <Buffer 02 03>
console.log(bufferFrom('test', 'utf8'))
//=> <Buffer 74 65 73 74>
const buf = bufferFrom('test')
console.log(bufferFrom(buf))
//=> <Buffer 74 65 73 74>
```
## API
### bufferFrom(array)
- `array` <Array>
Allocates a new `Buffer` using an `array` of octets.
### bufferFrom(arrayBuffer[, byteOffset[, length]])
- `arrayBuffer` <ArrayBuffer> The `.buffer` property of a TypedArray or ArrayBuffer
- `byteOffset` <Integer> Where to start copying from `arrayBuffer`. **Default:** `0`
- `length` <Integer> How many bytes to copy from `arrayBuffer`. **Default:** `arrayBuffer.length - byteOffset`
When passed a reference to the `.buffer` property of a TypedArray instance, the
newly created `Buffer` will share the same allocated memory as the TypedArray.
The optional `byteOffset` and `length` arguments specify a memory range within
the `arrayBuffer` that will be shared by the `Buffer`.
### bufferFrom(buffer)
- `buffer` <Buffer> An existing `Buffer` to copy data from
Copies the passed `buffer` data onto a new `Buffer` instance.
### bufferFrom(string[, encoding])
- `string` <String> A string to encode.
- `encoding` <String> The encoding of `string`. **Default:** `'utf8'`
Creates a new `Buffer` containing the given JavaScript string `string`. If
provided, the `encoding` parameter identifies the character encoding of
`string`.
## See also
- [buffer-alloc](https://github.com/LinusU/buffer-alloc) A ponyfill for `Buffer.alloc`
- [buffer-alloc-unsafe](https://github.com/LinusU/buffer-alloc-unsafe) A ponyfill for `Buffer.allocUnsafe`
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