buffer

What is buffer?

The 'buffer' npm package provides a way to handle binary data in Node.js. It implements the Buffer class, which is a global type for dealing with binary data directly. Buffers are similar to arrays of integers but correspond to fixed-sized, raw memory allocations outside the V8 heap. They are useful when working with TCP streams, file system operations, and other contexts where it's necessary to handle raw binary data.

What are buffer's main functionalities?

Creating Buffers

This code sample demonstrates how to create a new Buffer instance from a given string and encoding. The 'from' method is a static method on the Buffer class used to allocate a new Buffer that contains the given string.

const buffer = Buffer.from('Hello World', 'utf8');

Writing to Buffers

This code sample shows how to write to a buffer. The 'alloc' method creates a new Buffer of a specified size, and the 'write' method writes a string to the buffer at a specified offset using a given encoding.

const buffer = Buffer.alloc(10); buffer.write('Hello', 0, 'utf8');

Reading from Buffers

This code sample illustrates how to read data from a buffer. The 'toString' method converts the buffer's contents to a string using the specified encoding.

const buffer = Buffer.from('Hello World'); const string = buffer.toString('utf8');

Manipulating Buffers

This code sample demonstrates how to concatenate two buffers into a new buffer using the 'concat' method.

const buffer1 = Buffer.from('Hello'); const buffer2 = Buffer.from('World'); const concatenated = Buffer.concat([buffer1, buffer2]);

Buffer Slicing

This code sample shows how to create a new buffer that references the same memory as the original buffer but with the specified start and end indices, effectively creating a slice of the original buffer.

const buffer = Buffer.from('Hello World'); const slice = buffer.slice(0, 5);

Other packages similar to buffer

typedarray

The 'typedarray' package provides an implementation of Typed Arrays, which are array-like views of binary data buffers. While similar to Node.js Buffers, Typed Arrays are part of the ECMAScript standard and are available in browsers as well as Node.js.

bl

The 'bl' (Buffer List) package is a storage object for collections of Node.js Buffers. Unlike the Buffer class, which deals with single Buffer instances, 'bl' provides a way to join multiple buffers into one continuous buffer and still maintain access to the individual buffers.

concat-stream

The 'concat-stream' package is a writable stream that concatenates all the data from a stream and calls a callback with the result. It is similar to the Buffer.concat method but works with streams, collecting data chunks and concatenating them into a single buffer or string.

README

buffer

The buffer module from node.js, for the browser.

With browserify, 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. Read the official docs for the full list of properties, instance methods, and class methods that are supported.

features

• Manipulate binary data like a boss, in all browsers -- even IE6!
• Super fast. Backed by Typed Arrays (Uint8Array/ArrayBuffer, not Object)
• Extremely small bundle size (5.04KB minified + gzipped, 35.5KB with comments)
• Excellent browser support (IE 6+, Chrome 4+, Firefox 3+, Safari 5.1+, Opera 11+, iOS, etc.)
• Preserves Node API exactly, with one important difference (see below)
• .slice() returns instances of the same type (Buffer)
• Square-bracket buf[4] notation works, even in old browsers like IE6!
• 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:

npm install buffer

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

usage

The module's API is identical to node's Buffer API. Read the official docs 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 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:

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 are augmented with function properties for all the Buffer API functions. We use Uint8Array so that square bracket notation works as expected -- it returns a single octet. By augmenting the instances, we can avoid modifying the Uint8Array prototype.

differences

IMPORTANT: always use Buffer.isBuffer instead of instanceof Buffer

The Buffer constructor returns a Uint8Array (with all the Buffer methods added as properties on the instance) for performance reasons, so instanceof Buffer won't work. In node, you can use either Buffer.isBuffer or instanceof Buffer to check if an object is a Buffer. But, in the browser you must use Buffer.isBuffer to detect the special Uint8Array-based Buffers.

Minor: buf.slice() does not modify parent buffer's memory in old browsers

If you only support modern browsers (specifically, those with typed array support), then this issue does not affect you.

In node, the slice() method returns a new Buffer that shares underlying memory with the original Buffer. When you modify one buffer, you modify the other. Read more.

This works correctly in browsers with typed array support (* with the exception of Firefox older than version 30). Browsers that lack typed arrays get an alternate buffer implementation based on Object which has no mechanism to point separate Buffers to the same underlying slab of memory.

* Firefox older than version 30 gets the Object implementation -- not the typed arrays one -- because of this bug (now fixed!) that made it impossible to add properties to a typed array.

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, 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.

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.

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

JavaScript Standard Style

This module uses JavaScript Standard Style.

credit

This was originally forked from buffer-browserify.

license

MIT. Copyright (C) Feross Aboukhadijeh, and other contributors. Originally forked from an MIT-licensed module by Romain Beauxis.