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# 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` | |