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