# buffer [![travis][travis-image]][travis-url] [![npm][npm-image]][npm-url] [![downloads][downloads-image]][downloads-url] [![javascript style guide][standard-image]][standard-url]

[travis-image]: https://img.shields.io/travis/feross/buffer/master.svg
[travis-url]: https://travis-ci.org/feross/buffer
[npm-image]: https://img.shields.io/npm/v/buffer.svg
[npm-url]: https://npmjs.org/package/buffer
[downloads-image]: https://img.shields.io/npm/dm/buffer.svg
[downloads-url]: https://npmjs.org/package/buffer
[standard-image]: https://img.shields.io/badge/code_style-standard-brightgreen.svg
[standard-url]: https://standardjs.com

#### The buffer module from [node.js](https://nodejs.org/), for the browser.

[![saucelabs][saucelabs-image]][saucelabs-url]

[saucelabs-image]: https://saucelabs.com/browser-matrix/buffer.svg
[saucelabs-url]: https://saucelabs.com/u/buffer

With [browserify](http://browserify.org), simply `require('buffer')` or use the `Buffer` global and you will get this module.

The goal is to provide an API that is 100% identical to
[node's Buffer API](https://nodejs.org/api/buffer.html). Read the
[official docs](https://nodejs.org/api/buffer.html) for the full list of properties,
instance methods, and class methods that are supported.

## features

- Manipulate binary data like a boss, in all browsers!
- Super fast. Backed by Typed Arrays (`Uint8Array`/`ArrayBuffer`, not `Object`)
- Extremely small bundle size (**6.75KB minified + gzipped**, 51.9KB with comments)
- Excellent browser support (Chrome, Firefox, Edge, Safari 9+, IE 11, iOS 9+, Android, etc.)
- Preserves Node API exactly, with one minor difference (see below)
- Square-bracket `buf[4]` notation works!
- Does not modify any browser prototypes or put anything on `window`
- Comprehensive test suite (including all buffer tests from node.js core)

## install

To use this module directly (without browserify), install it:

```bash
npm install buffer
```

This module was previously called **native-buffer-browserify**, but please use **buffer**
from now on.

If you do not use a bundler, you can use the [standalone script](https://bundle.run/buffer).

## usage

The module's API is identical to node's `Buffer` API. Read the
[official docs](https://nodejs.org/api/buffer.html) for the full list of properties,
instance methods, and class methods that are supported.

As mentioned above, `require('buffer')` or use the `Buffer` global with
[browserify](http://browserify.org) and this module will automatically be included
in your bundle. Almost any npm module will work in the browser, even if it assumes that
the node `Buffer` API will be available.

To depend on this module explicitly (without browserify), require it like this:

```js
var Buffer = require("buffer/").Buffer; // note: the trailing slash is important!
```

To require this module explicitly, use `require('buffer/')` which tells the node.js module
lookup algorithm (also used by browserify) to use the **npm module** named `buffer`
instead of the **node.js core** module named `buffer`!

## how does it work?

The Buffer constructor returns instances of `Uint8Array` that have their prototype
changed to `Buffer.prototype`. Furthermore, `Buffer` is a subclass of `Uint8Array`,
so the returned instances will have all the node `Buffer` methods and the
`Uint8Array` methods. Square bracket notation works as expected -- it returns a
single octet.

The `Uint8Array` prototype remains unmodified.

## tracking the latest node api

This module tracks the Buffer API in the latest (unstable) version of node.js. The Buffer
API is considered **stable** in the
[node stability index](https://nodejs.org/docs/latest/api/documentation.html#documentation_stability_index),
so it is unlikely that there will ever be breaking changes.
Nonetheless, when/if the Buffer API changes in node, this module's API will change
accordingly.

## related packages

- [`buffer-reverse`](https://www.npmjs.com/package/buffer-reverse) - Reverse a buffer
- [`buffer-xor`](https://www.npmjs.com/package/buffer-xor) - Bitwise xor a buffer
- [`is-buffer`](https://www.npmjs.com/package/is-buffer) - Determine if an object is a Buffer without including the whole `Buffer` package

## conversion packages

### convert typed array to buffer

Use [`typedarray-to-buffer`](https://www.npmjs.com/package/typedarray-to-buffer) to convert any kind of typed array to a `Buffer`. Does not perform a copy, so it's super fast.

### convert buffer to typed array

`Buffer` is a subclass of `Uint8Array` (which is a typed array). So there is no need to explicitly convert to typed array. Just use the buffer as a `Uint8Array`.

### convert blob to buffer

Use [`blob-to-buffer`](https://www.npmjs.com/package/blob-to-buffer) to convert a `Blob` to a `Buffer`.

### convert buffer to blob

To convert a `Buffer` to a `Blob`, use the `Blob` constructor:

```js
var blob = new Blob([buffer]);
```

Optionally, specify a mimetype:

```js
var blob = new Blob([buffer], { type: "text/html" });
```

### convert arraybuffer to buffer

To convert an `ArrayBuffer` to a `Buffer`, use the `Buffer.from` function. Does not perform a copy, so it's super fast.

```js
var buffer = Buffer.from(arrayBuffer);
```

### convert buffer to arraybuffer

To convert a `Buffer` to an `ArrayBuffer`, use the `.buffer` property (which is present on all `Uint8Array` objects):

```js
var arrayBuffer = buffer.buffer.slice(
  buffer.byteOffset,
  buffer.byteOffset + buffer.byteLength
);
```

Alternatively, use the [`to-arraybuffer`](https://www.npmjs.com/package/to-arraybuffer) module.

## performance

See perf tests in `/perf`.

`BrowserBuffer` is the browser `buffer` module (this repo). `Uint8Array` is included as a
sanity check (since `BrowserBuffer` uses `Uint8Array` under the hood, `Uint8Array` will
always be at least a bit faster). Finally, `NodeBuffer` is the node.js buffer module,
which is included to compare against.

NOTE: Performance has improved since these benchmarks were taken. PR welcome to update the README.

### Chrome 38

| Method                         | Operations         | Accuracy | Sampled | Fastest |
| :----------------------------- | :----------------- | :------- | :------ | :-----: |
| BrowserBuffer#bracket-notation | 11,457,464 ops/sec | ±0.86%   | 66      |    ✓    |
| Uint8Array#bracket-notation    | 10,824,332 ops/sec | ±0.74%   | 65      |         |
|                                |                    |          |         |
| BrowserBuffer#concat           | 450,532 ops/sec    | ±0.76%   | 68      |         |
| Uint8Array#concat              | 1,368,911 ops/sec  | ±1.50%   | 62      |    ✓    |
|                                |                    |          |         |
| BrowserBuffer#copy(16000)      | 903,001 ops/sec    | ±0.96%   | 67      |         |
| Uint8Array#copy(16000)         | 1,422,441 ops/sec  | ±1.04%   | 66      |    ✓    |
|                                |                    |          |         |
| BrowserBuffer#copy(16)         | 11,431,358 ops/sec | ±0.46%   | 69      |         |
| Uint8Array#copy(16)            | 13,944,163 ops/sec | ±1.12%   | 68      |    ✓    |
|                                |                    |          |         |
| BrowserBuffer#new(16000)       | 106,329 ops/sec    | ±6.70%   | 44      |         |
| Uint8Array#new(16000)          | 131,001 ops/sec    | ±2.85%   | 31      |    ✓    |
|                                |                    |          |         |
| BrowserBuffer#new(16)          | 1,554,491 ops/sec  | ±1.60%   | 65      |         |
| Uint8Array#new(16)             | 6,623,930 ops/sec  | ±1.66%   | 65      |    ✓    |
|                                |                    |          |         |
| BrowserBuffer#readDoubleBE     | 112,830 ops/sec    | ±0.51%   | 69      |    ✓    |
| DataView#getFloat64            | 93,500 ops/sec     | ±0.57%   | 68      |         |
|                                |                    |          |         |
| BrowserBuffer#readFloatBE      | 146,678 ops/sec    | ±0.95%   | 68      |    ✓    |
| DataView#getFloat32            | 99,311 ops/sec     | ±0.41%   | 67      |         |
|                                |                    |          |         |
| BrowserBuffer#readUInt32LE     | 843,214 ops/sec    | ±0.70%   | 69      |    ✓    |
| DataView#getUint32             | 103,024 ops/sec    | ±0.64%   | 67      |         |
|                                |                    |          |         |
| BrowserBuffer#slice            | 1,013,941 ops/sec  | ±0.75%   | 67      |         |
| Uint8Array#subarray            | 1,903,928 ops/sec  | ±0.53%   | 67      |    ✓    |
|                                |                    |          |         |
| BrowserBuffer#writeFloatBE     | 61,387 ops/sec     | ±0.90%   | 67      |         |
| DataView#setFloat32            | 141,249 ops/sec    | ±0.40%   | 66      |    ✓    |

### Firefox 33

| Method                         | Operations         | Accuracy | Sampled | Fastest |
| :----------------------------- | :----------------- | :------- | :------ | :-----: |
| BrowserBuffer#bracket-notation | 20,800,421 ops/sec | ±1.84%   | 60      |         |
| Uint8Array#bracket-notation    | 20,826,235 ops/sec | ±2.02%   | 61      |    ✓    |
|                                |                    |          |         |
| BrowserBuffer#concat           | 153,076 ops/sec    | ±2.32%   | 61      |         |
| Uint8Array#concat              | 1,255,674 ops/sec  | ±8.65%   | 52      |    ✓    |
|                                |                    |          |         |
| BrowserBuffer#copy(16000)      | 1,105,312 ops/sec  | ±1.16%   | 63      |         |
| Uint8Array#copy(16000)         | 1,615,911 ops/sec  | ±0.55%   | 66      |    ✓    |
|                                |                    |          |         |
| BrowserBuffer#copy(16)         | 16,357,599 ops/sec | ±0.73%   | 68      |         |
| Uint8Array#copy(16)            | 31,436,281 ops/sec | ±1.05%   | 68      |    ✓    |
|                                |                    |          |         |
| BrowserBuffer#new(16000)       | 52,995 ops/sec     | ±6.01%   | 35      |         |
| Uint8Array#new(16000)          | 87,686 ops/sec     | ±5.68%   | 45      |    ✓    |
|                                |                    |          |         |
| BrowserBuffer#new(16)          | 252,031 ops/sec    | ±1.61%   | 66      |         |
| Uint8Array#new(16)             | 8,477,026 ops/sec  | ±0.49%   | 68      |    ✓    |
|                                |                    |          |         |
| BrowserBuffer#readDoubleBE     | 99,871 ops/sec     | ±0.41%   | 69      |         |
| DataView#getFloat64            | 285,663 ops/sec    | ±0.70%   | 68      |    ✓    |
|                                |                    |          |         |
| BrowserBuffer#readFloatBE      | 115,540 ops/sec    | ±0.42%   | 69      |         |
| DataView#getFloat32            | 288,722 ops/sec    | ±0.82%   | 68      |    ✓    |
|                                |                    |          |         |
| BrowserBuffer#readUInt32LE     | 633,926 ops/sec    | ±1.08%   | 67      |    ✓    |
| DataView#getUint32             | 294,808 ops/sec    | ±0.79%   | 64      |         |
|                                |                    |          |         |
| BrowserBuffer#slice            | 349,425 ops/sec    | ±0.46%   | 69      |         |
| Uint8Array#subarray            | 5,965,819 ops/sec  | ±0.60%   | 65      |    ✓    |
|                                |                    |          |         |
| BrowserBuffer#writeFloatBE     | 59,980 ops/sec     | ±0.41%   | 67      |         |
| DataView#setFloat32            | 317,634 ops/sec    | ±0.63%   | 68      |    ✓    |

### Safari 8

| Method                         | Operations         | Accuracy | Sampled | Fastest |
| :----------------------------- | :----------------- | :------- | :------ | :-----: |
| BrowserBuffer#bracket-notation | 10,279,729 ops/sec | ±2.25%   | 56      |    ✓    |
| Uint8Array#bracket-notation    | 10,030,767 ops/sec | ±2.23%   | 59      |         |
|                                |                    |          |         |
| BrowserBuffer#concat           | 144,138 ops/sec    | ±1.38%   | 65      |         |
| Uint8Array#concat              | 4,950,764 ops/sec  | ±1.70%   | 63      |    ✓    |
|                                |                    |          |         |
| BrowserBuffer#copy(16000)      | 1,058,548 ops/sec  | ±1.51%   | 64      |         |
| Uint8Array#copy(16000)         | 1,409,666 ops/sec  | ±1.17%   | 65      |    ✓    |
|                                |                    |          |         |
| BrowserBuffer#copy(16)         | 6,282,529 ops/sec  | ±1.88%   | 58      |         |
| Uint8Array#copy(16)            | 11,907,128 ops/sec | ±2.87%   | 58      |    ✓    |
|                                |                    |          |         |
| BrowserBuffer#new(16000)       | 101,663 ops/sec    | ±3.89%   | 57      |         |
| Uint8Array#new(16000)          | 22,050,818 ops/sec | ±6.51%   | 46      |    ✓    |
|                                |                    |          |         |
| BrowserBuffer#new(16)          | 176,072 ops/sec    | ±2.13%   | 64      |         |
| Uint8Array#new(16)             | 24,385,731 ops/sec | ±5.01%   | 51      |    ✓    |
|                                |                    |          |         |
| BrowserBuffer#readDoubleBE     | 41,341 ops/sec     | ±1.06%   | 67      |         |
| DataView#getFloat64            | 322,280 ops/sec    | ±0.84%   | 68      |    ✓    |
|                                |                    |          |         |
| BrowserBuffer#readFloatBE      | 46,141 ops/sec     | ±1.06%   | 65      |         |
| DataView#getFloat32            | 337,025 ops/sec    | ±0.43%   | 69      |    ✓    |
|                                |                    |          |         |
| BrowserBuffer#readUInt32LE     | 151,551 ops/sec    | ±1.02%   | 66      |         |
| DataView#getUint32             | 308,278 ops/sec    | ±0.94%   | 67      |    ✓    |
|                                |                    |          |         |
| BrowserBuffer#slice            | 197,365 ops/sec    | ±0.95%   | 66      |         |
| Uint8Array#subarray            | 9,558,024 ops/sec  | ±3.08%   | 58      |    ✓    |
|                                |                    |          |         |
| BrowserBuffer#writeFloatBE     | 17,518 ops/sec     | ±1.03%   | 63      |         |
| DataView#setFloat32            | 319,751 ops/sec    | ±0.48%   | 68      |    ✓    |

### Node 0.11.14

| Method                         | Operations         | Accuracy | Sampled | Fastest |
| :----------------------------- | :----------------- | :------- | :------ | :-----: |
| BrowserBuffer#bracket-notation | 10,489,828 ops/sec | ±3.25%   | 90      |         |
| Uint8Array#bracket-notation    | 10,534,884 ops/sec | ±0.81%   | 92      |    ✓    |
| NodeBuffer#bracket-notation    | 10,389,910 ops/sec | ±0.97%   | 87      |         |
|                                |                    |          |         |
| BrowserBuffer#concat           | 487,830 ops/sec    | ±2.58%   | 88      |         |
| Uint8Array#concat              | 1,814,327 ops/sec  | ±1.28%   | 88      |    ✓    |
| NodeBuffer#concat              | 1,636,523 ops/sec  | ±1.88%   | 73      |         |
|                                |                    |          |         |
| BrowserBuffer#copy(16000)      | 1,073,665 ops/sec  | ±0.77%   | 90      |         |
| Uint8Array#copy(16000)         | 1,348,517 ops/sec  | ±0.84%   | 89      |    ✓    |
| NodeBuffer#copy(16000)         | 1,289,533 ops/sec  | ±0.82%   | 93      |         |
|                                |                    |          |         |
| BrowserBuffer#copy(16)         | 12,782,706 ops/sec | ±0.74%   | 85      |         |
| Uint8Array#copy(16)            | 14,180,427 ops/sec | ±0.93%   | 92      |    ✓    |
| NodeBuffer#copy(16)            | 11,083,134 ops/sec | ±1.06%   | 89      |         |
|                                |                    |          |         |
| BrowserBuffer#new(16000)       | 141,678 ops/sec    | ±3.30%   | 67      |         |
| Uint8Array#new(16000)          | 161,491 ops/sec    | ±2.96%   | 60      |         |
| NodeBuffer#new(16000)          | 292,699 ops/sec    | ±3.20%   | 55      |    ✓    |
|                                |                    |          |         |
| BrowserBuffer#new(16)          | 1,655,466 ops/sec  | ±2.41%   | 82      |         |
| Uint8Array#new(16)             | 14,399,926 ops/sec | ±0.91%   | 94      |    ✓    |
| NodeBuffer#new(16)             | 3,894,696 ops/sec  | ±0.88%   | 92      |         |
|                                |                    |          |         |
| BrowserBuffer#readDoubleBE     | 109,582 ops/sec    | ±0.75%   | 93      |    ✓    |
| DataView#getFloat64            | 91,235 ops/sec     | ±0.81%   | 90      |         |
| NodeBuffer#readDoubleBE        | 88,593 ops/sec     | ±0.96%   | 81      |         |
|                                |                    |          |         |
| BrowserBuffer#readFloatBE      | 139,854 ops/sec    | ±1.03%   | 85      |    ✓    |
| DataView#getFloat32            | 98,744 ops/sec     | ±0.80%   | 89      |         |
| NodeBuffer#readFloatBE         | 92,769 ops/sec     | ±0.94%   | 93      |         |
|                                |                    |          |         |
| BrowserBuffer#readUInt32LE     | 710,861 ops/sec    | ±0.82%   | 92      |         |
| DataView#getUint32             | 117,893 ops/sec    | ±0.84%   | 91      |         |
| NodeBuffer#readUInt32LE        | 851,412 ops/sec    | ±0.72%   | 93      |    ✓    |
|                                |                    |          |         |
| BrowserBuffer#slice            | 1,673,877 ops/sec  | ±0.73%   | 94      |         |
| Uint8Array#subarray            | 6,919,243 ops/sec  | ±0.67%   | 90      |    ✓    |
| NodeBuffer#slice               | 4,617,604 ops/sec  | ±0.79%   | 93      |         |
|                                |                    |          |         |
| BrowserBuffer#writeFloatBE     | 66,011 ops/sec     | ±0.75%   | 93      |         |
| DataView#setFloat32            | 127,760 ops/sec    | ±0.72%   | 93      |    ✓    |
| NodeBuffer#writeFloatBE        | 103,352 ops/sec    | ±0.83%   | 93      |         |

### iojs 1.8.1

| Method                         | Operations         | Accuracy | Sampled | Fastest |
| :----------------------------- | :----------------- | :------- | :------ | :-----: |
| BrowserBuffer#bracket-notation | 10,990,488 ops/sec | ±1.11%   | 91      |         |
| Uint8Array#bracket-notation    | 11,268,757 ops/sec | ±0.65%   | 97      |         |
| NodeBuffer#bracket-notation    | 11,353,260 ops/sec | ±0.83%   | 94      |    ✓    |
|                                |                    |          |         |
| BrowserBuffer#concat           | 378,954 ops/sec    | ±0.74%   | 94      |         |
| Uint8Array#concat              | 1,358,288 ops/sec  | ±0.97%   | 87      |         |
| NodeBuffer#concat              | 1,934,050 ops/sec  | ±1.11%   | 78      |    ✓    |
|                                |                    |          |         |
| BrowserBuffer#copy(16000)      | 894,538 ops/sec    | ±0.56%   | 84      |         |
| Uint8Array#copy(16000)         | 1,442,656 ops/sec  | ±0.71%   | 96      |         |
| NodeBuffer#copy(16000)         | 1,457,898 ops/sec  | ±0.53%   | 92      |    ✓    |
|                                |                    |          |         |
| BrowserBuffer#copy(16)         | 12,870,457 ops/sec | ±0.67%   | 95      |         |
| Uint8Array#copy(16)            | 16,643,989 ops/sec | ±0.61%   | 93      |    ✓    |
| NodeBuffer#copy(16)            | 14,885,848 ops/sec | ±0.74%   | 94      |         |
|                                |                    |          |         |
| BrowserBuffer#new(16000)       | 109,264 ops/sec    | ±4.21%   | 63      |         |
| Uint8Array#new(16000)          | 138,916 ops/sec    | ±1.87%   | 61      |         |
| NodeBuffer#new(16000)          | 281,449 ops/sec    | ±3.58%   | 51      |    ✓    |
|                                |                    |          |         |
| BrowserBuffer#new(16)          | 1,362,935 ops/sec  | ±0.56%   | 99      |         |
| Uint8Array#new(16)             | 6,193,090 ops/sec  | ±0.64%   | 95      |    ✓    |
| NodeBuffer#new(16)             | 4,745,425 ops/sec  | ±1.56%   | 90      |         |
|                                |                    |          |         |
| BrowserBuffer#readDoubleBE     | 118,127 ops/sec    | ±0.59%   | 93      |    ✓    |
| DataView#getFloat64            | 107,332 ops/sec    | ±0.65%   | 91      |         |
| NodeBuffer#readDoubleBE        | 116,274 ops/sec    | ±0.94%   | 95      |         |
|                                |                    |          |         |
| BrowserBuffer#readFloatBE      | 150,326 ops/sec    | ±0.58%   | 95      |    ✓    |
| DataView#getFloat32            | 110,541 ops/sec    | ±0.57%   | 98      |         |
| NodeBuffer#readFloatBE         | 121,599 ops/sec    | ±0.60%   | 87      |         |
|                                |                    |          |         |
| BrowserBuffer#readUInt32LE     | 814,147 ops/sec    | ±0.62%   | 93      |         |
| DataView#getUint32             | 137,592 ops/sec    | ±0.64%   | 90      |         |
| NodeBuffer#readUInt32LE        | 931,650 ops/sec    | ±0.71%   | 96      |    ✓    |
|                                |                    |          |         |
| BrowserBuffer#slice            | 878,590 ops/sec    | ±0.68%   | 93      |         |
| Uint8Array#subarray            | 2,843,308 ops/sec  | ±1.02%   | 90      |         |
| NodeBuffer#slice               | 4,998,316 ops/sec  | ±0.68%   | 90      |    ✓    |
|                                |                    |          |         |
| BrowserBuffer#writeFloatBE     | 65,927 ops/sec     | ±0.74%   | 93      |         |
| DataView#setFloat32            | 139,823 ops/sec    | ±0.97%   | 89      |    ✓    |
| NodeBuffer#writeFloatBE        | 135,763 ops/sec    | ±0.65%   | 96      |         |
|                                |                    |          |         |

## Testing the project

First, install the project:

    npm install

Then, to run tests in Node.js, run:

    npm run test-node

To test locally in a browser, you can run:

    npm run test-browser-es5-local # For ES5 browsers that don't support ES6
    npm run test-browser-es6-local # For ES6 compliant browsers

This will print out a URL that you can then open in a browser to run the tests, using [airtap](https://www.npmjs.com/package/airtap).

To run automated browser tests using Saucelabs, ensure that your `SAUCE_USERNAME` and `SAUCE_ACCESS_KEY` environment variables are set, then run:

    npm test

This is what's run in Travis, to check against various browsers. The list of browsers is kept in the `bin/airtap-es5.yml` and `bin/airtap-es6.yml` files.

## JavaScript Standard Style

This module uses [JavaScript Standard Style](https://github.com/feross/standard).

[![JavaScript Style Guide](https://cdn.rawgit.com/feross/standard/master/badge.svg)](https://github.com/feross/standard)

To test that the code conforms to the style, `npm install` and run:

    ./node_modules/.bin/standard

## credit

This was originally forked from [buffer-browserify](https://github.com/toots/buffer-browserify).

## Security Policies and Procedures

The `buffer` team and community take all security bugs in `buffer` seriously. Please see our [security policies and procedures](https://github.com/feross/security) document to learn how to report issues.

## license

MIT. Copyright (C) [Feross Aboukhadijeh](http://feross.org), and other contributors. Originally forked from an MIT-licensed module by Romain Beauxis.
