Source Code: lib/buffer.js
\nBuffer objects are used to represent a fixed-length sequence of bytes. Many\nNode.js APIs support Buffers.
The Buffer class is a subclass of JavaScript's Uint8Array class and\nextends it with methods that cover additional use cases. Node.js APIs accept\nplain Uint8Arrays wherever Buffers are supported as well.
While the Buffer class is available within the global scope, it is still\nrecommended to explicitly reference it via an import or require statement.
import { Buffer } from 'buffer';\n\n// Creates a zero-filled Buffer of length 10.\nconst buf1 = Buffer.alloc(10);\n\n// Creates a Buffer of length 10,\n// filled with bytes which all have the value `1`.\nconst buf2 = Buffer.alloc(10, 1);\n\n// Creates an uninitialized buffer of length 10.\n// This is faster than calling Buffer.alloc() but the returned\n// Buffer instance might contain old data that needs to be\n// overwritten using fill(), write(), or other functions that fill the Buffer's\n// contents.\nconst buf3 = Buffer.allocUnsafe(10);\n\n// Creates a Buffer containing the bytes [1, 2, 3].\nconst buf4 = Buffer.from([1, 2, 3]);\n\n// Creates a Buffer containing the bytes [1, 1, 1, 1] – the entries\n// are all truncated using `(value & 255)` to fit into the range 0–255.\nconst buf5 = Buffer.from([257, 257.5, -255, '1']);\n\n// Creates a Buffer containing the UTF-8-encoded bytes for the string 'tést':\n// [0x74, 0xc3, 0xa9, 0x73, 0x74] (in hexadecimal notation)\n// [116, 195, 169, 115, 116] (in decimal notation)\nconst buf6 = Buffer.from('tést');\n\n// Creates a Buffer containing the Latin-1 bytes [0x74, 0xe9, 0x73, 0x74].\nconst buf7 = Buffer.from('tést', 'latin1');\nconst { Buffer } = require('buffer');\n\n// Creates a zero-filled Buffer of length 10.\nconst buf1 = Buffer.alloc(10);\n\n// Creates a Buffer of length 10,\n// filled with bytes which all have the value `1`.\nconst buf2 = Buffer.alloc(10, 1);\n\n// Creates an uninitialized buffer of length 10.\n// This is faster than calling Buffer.alloc() but the returned\n// Buffer instance might contain old data that needs to be\n// overwritten using fill(), write(), or other functions that fill the Buffer's\n// contents.\nconst buf3 = Buffer.allocUnsafe(10);\n\n// Creates a Buffer containing the bytes [1, 2, 3].\nconst buf4 = Buffer.from([1, 2, 3]);\n\n// Creates a Buffer containing the bytes [1, 1, 1, 1] – the entries\n// are all truncated using `(value & 255)` to fit into the range 0–255.\nconst buf5 = Buffer.from([257, 257.5, -255, '1']);\n\n// Creates a Buffer containing the UTF-8-encoded bytes for the string 'tést':\n// [0x74, 0xc3, 0xa9, 0x73, 0x74] (in hexadecimal notation)\n// [116, 195, 169, 115, 116] (in decimal notation)\nconst buf6 = Buffer.from('tést');\n\n// Creates a Buffer containing the Latin-1 bytes [0x74, 0xe9, 0x73, 0x74].\nconst buf7 = Buffer.from('tést', 'latin1');\nWhen converting between Buffers and strings, a character encoding may be\nspecified. If no character encoding is specified, UTF-8 will be used as the\ndefault.
import { Buffer } from 'buffer';\n\nconst buf = Buffer.from('hello world', 'utf8');\n\nconsole.log(buf.toString('hex'));\n// Prints: 68656c6c6f20776f726c64\nconsole.log(buf.toString('base64'));\n// Prints: aGVsbG8gd29ybGQ=\n\nconsole.log(Buffer.from('fhqwhgads', 'utf8'));\n// Prints: <Buffer 66 68 71 77 68 67 61 64 73>\nconsole.log(Buffer.from('fhqwhgads', 'utf16le'));\n// Prints: <Buffer 66 00 68 00 71 00 77 00 68 00 67 00 61 00 64 00 73 00>\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.from('hello world', 'utf8');\n\nconsole.log(buf.toString('hex'));\n// Prints: 68656c6c6f20776f726c64\nconsole.log(buf.toString('base64'));\n// Prints: aGVsbG8gd29ybGQ=\n\nconsole.log(Buffer.from('fhqwhgads', 'utf8'));\n// Prints: <Buffer 66 68 71 77 68 67 61 64 73>\nconsole.log(Buffer.from('fhqwhgads', 'utf16le'));\n// Prints: <Buffer 66 00 68 00 71 00 77 00 68 00 67 00 61 00 64 00 73 00>\nNode.js buffers accept all case variations of encoding strings that they\nreceive. For example, UTF-8 can be specified as 'utf8', 'UTF8' or 'uTf8'.
The character encodings currently supported by Node.js are the following:
\n'utf8' (alias: 'utf-8'): Multi-byte encoded Unicode characters. Many web\npages and other document formats use UTF-8. This is the default character\nencoding. When decoding a Buffer into a string that does not exclusively\ncontain valid UTF-8 data, the Unicode replacement character U+FFFD � will be\nused to represent those errors.
'utf16le' (alias: 'utf-16le'): Multi-byte encoded Unicode characters.\nUnlike 'utf8', each character in the string will be encoded using either 2\nor 4 bytes. Node.js only supports the little-endian variant of\nUTF-16.
'latin1': Latin-1 stands for ISO-8859-1. This character encoding only\nsupports the Unicode characters from U+0000 to U+00FF. Each character is\nencoded using a single byte. Characters that do not fit into that range are\ntruncated and will be mapped to characters in that range.
Converting a Buffer into a string using one of the above is referred to as\ndecoding, and converting a string into a Buffer is referred to as encoding.
Node.js also supports the following binary-to-text encodings. For\nbinary-to-text encodings, the naming convention is reversed: Converting a\nBuffer into a string is typically referred to as encoding, and converting a\nstring into a Buffer as decoding.
'base64': Base64 encoding. When creating a Buffer from a string,\nthis encoding will also correctly accept \"URL and Filename Safe Alphabet\" as\nspecified in RFC 4648, Section 5. Whitespace characters such as spaces,\ntabs, and new lines contained within the base64-encoded string are ignored.
'base64url': base64url encoding as specified in\nRFC 4648, Section 5. When creating a Buffer from a string, this\nencoding will also correctly accept regular base64-encoded strings. When\nencoding a Buffer to a string, this encoding will omit padding.
'hex': Encode each byte as two hexadecimal characters. Data truncation\nmay occur when decoding strings that do exclusively contain valid hexadecimal\ncharacters. See below for an example.
The following legacy character encodings are also supported:
\n'ascii': For 7-bit ASCII data only. When encoding a string into a\nBuffer, this is equivalent to using 'latin1'. When decoding a Buffer\ninto a string, using this encoding will additionally unset the highest bit of\neach byte before decoding as 'latin1'.\nGenerally, there should be no reason to use this encoding, as 'utf8'\n(or, if the data is known to always be ASCII-only, 'latin1') will be a\nbetter choice when encoding or decoding ASCII-only text. It is only provided\nfor legacy compatibility.
'binary': Alias for 'latin1'. See binary strings for more background\non this topic. The name of this encoding can be very misleading, as all of the\nencodings listed here convert between strings and binary data. For converting\nbetween strings and Buffers, typically 'utf8' is the right choice.
'ucs2', 'ucs-2': Aliases of 'utf16le'. UCS-2 used to refer to a variant\nof UTF-16 that did not support characters that had code points larger than\nU+FFFF. In Node.js, these code points are always supported.
import { Buffer } from 'buffer';\n\nBuffer.from('1ag', 'hex');\n// Prints <Buffer 1a>, data truncated when first non-hexadecimal value\n// ('g') encountered.\n\nBuffer.from('1a7g', 'hex');\n// Prints <Buffer 1a>, data truncated when data ends in single digit ('7').\n\nBuffer.from('1634', 'hex');\n// Prints <Buffer 16 34>, all data represented.\nconst { Buffer } = require('buffer');\n\nBuffer.from('1ag', 'hex');\n// Prints <Buffer 1a>, data truncated when first non-hexadecimal value\n// ('g') encountered.\n\nBuffer.from('1a7g', 'hex');\n// Prints <Buffer 1a>, data truncated when data ends in single digit ('7').\n\nBuffer.from('1634', 'hex');\n// Prints <Buffer 16 34>, all data represented.\nModern Web browsers follow the WHATWG Encoding Standard which aliases\nboth 'latin1' and 'ISO-8859-1' to 'win-1252'. This means that while doing\nsomething like http.get(), if the returned charset is one of those listed in\nthe WHATWG specification it is possible that the server actually returned\n'win-1252'-encoded data, and using 'latin1' encoding may incorrectly decode\nthe characters.
Buffer instances are also JavaScript Uint8Array and TypedArray\ninstances. All TypedArray methods are available on Buffers. There are,\nhowever, subtle incompatibilities between the Buffer API and the\nTypedArray API.
In particular:
\nTypedArray.prototype.slice() creates a copy of part of the TypedArray,\nBuffer.prototype.slice() creates a view over the existing Buffer\nwithout copying. This behavior can be surprising, and only exists for legacy\ncompatibility. TypedArray.prototype.subarray() can be used to achieve\nthe behavior of Buffer.prototype.slice() on both Buffers\nand other TypedArrays.buf.toString() is incompatible with its TypedArray equivalent.buf.indexOf(), support additional arguments.There are two ways to create new TypedArray instances from a Buffer:
Buffer to a TypedArray constructor will copy the Buffers\ncontents, interpreted as an array of integers, and not as a byte sequence\nof the target type.import { Buffer } from 'buffer';\n\nconst buf = Buffer.from([1, 2, 3, 4]);\nconst uint32array = new Uint32Array(buf);\n\nconsole.log(uint32array);\n\n// Prints: Uint32Array(4) [ 1, 2, 3, 4 ]\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.from([1, 2, 3, 4]);\nconst uint32array = new Uint32Array(buf);\n\nconsole.log(uint32array);\n\n// Prints: Uint32Array(4) [ 1, 2, 3, 4 ]\nBuffers underlying ArrayBuffer will create a\nTypedArray that shares its memory with the Buffer.import { Buffer } from 'buffer';\n\nconst buf = Buffer.from('hello', 'utf16le');\nconst uint16array = new Uint16Array(\n buf.buffer,\n buf.byteOffset,\n buf.length / Uint16Array.BYTES_PER_ELEMENT);\n\nconsole.log(uint16array);\n\n// Prints: Uint16Array(5) [ 104, 101, 108, 108, 111 ]\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.from('hello', 'utf16le');\nconst uint16array = new Uint16Array(\n buf.buffer,\n buf.byteOffset,\n buf.length / Uint16Array.BYTES_PER_ELEMENT);\n\nconsole.log(uint16array);\n\n// Prints: Uint16Array(5) [ 104, 101, 108, 108, 111 ]\nIt is possible to create a new Buffer that shares the same allocated\nmemory as a TypedArray instance by using the TypedArray object’s\n.buffer property in the same way. Buffer.from()\nbehaves like new Uint8Array() in this context.
import { Buffer } from 'buffer';\n\nconst arr = new Uint16Array(2);\n\narr[0] = 5000;\narr[1] = 4000;\n\n// Copies the contents of `arr`.\nconst buf1 = Buffer.from(arr);\n\n// Shares memory with `arr`.\nconst buf2 = Buffer.from(arr.buffer);\n\nconsole.log(buf1);\n// Prints: <Buffer 88 a0>\nconsole.log(buf2);\n// Prints: <Buffer 88 13 a0 0f>\n\narr[1] = 6000;\n\nconsole.log(buf1);\n// Prints: <Buffer 88 a0>\nconsole.log(buf2);\n// Prints: <Buffer 88 13 70 17>\nconst { Buffer } = require('buffer');\n\nconst arr = new Uint16Array(2);\n\narr[0] = 5000;\narr[1] = 4000;\n\n// Copies the contents of `arr`.\nconst buf1 = Buffer.from(arr);\n\n// Shares memory with `arr`.\nconst buf2 = Buffer.from(arr.buffer);\n\nconsole.log(buf1);\n// Prints: <Buffer 88 a0>\nconsole.log(buf2);\n// Prints: <Buffer 88 13 a0 0f>\n\narr[1] = 6000;\n\nconsole.log(buf1);\n// Prints: <Buffer 88 a0>\nconsole.log(buf2);\n// Prints: <Buffer 88 13 70 17>\nWhen creating a Buffer using a TypedArray's .buffer, it is\npossible to use only a portion of the underlying ArrayBuffer by passing in\nbyteOffset and length parameters.
import { Buffer } from 'buffer';\n\nconst arr = new Uint16Array(20);\nconst buf = Buffer.from(arr.buffer, 0, 16);\n\nconsole.log(buf.length);\n// Prints: 16\nconst { Buffer } = require('buffer');\n\nconst arr = new Uint16Array(20);\nconst buf = Buffer.from(arr.buffer, 0, 16);\n\nconsole.log(buf.length);\n// Prints: 16\nThe Buffer.from() and TypedArray.from() have different signatures and\nimplementations. Specifically, the TypedArray variants accept a second\nargument that is a mapping function that is invoked on every element of the\ntyped array:
TypedArray.from(source[, mapFn[, thisArg]])The Buffer.from() method, however, does not support the use of a mapping\nfunction:
Buffer.from(array)Buffer.from(buffer)Buffer.from(arrayBuffer[, byteOffset[, length]])Buffer.from(string[, encoding])Buffer instances can be iterated over using for..of syntax:
import { Buffer } from 'buffer';\n\nconst buf = Buffer.from([1, 2, 3]);\n\nfor (const b of buf) {\n console.log(b);\n}\n// Prints:\n// 1\n// 2\n// 3\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.from([1, 2, 3]);\n\nfor (const b of buf) {\n console.log(b);\n}\n// Prints:\n// 1\n// 2\n// 3\nAdditionally, the buf.values(), buf.keys(), and\nbuf.entries() methods can be used to create iterators.
While, the Buffer object is available as a global, there are additional\nBuffer-related APIs that are available only via the buffer module\naccessed using require('buffer').
Decodes a string of Base64-encoded data into bytes, and encodes those bytes\ninto a string using Latin-1 (ISO-8859-1).
\nThe data may be any JavaScript-value that can be coerced into a string.
This function is only provided for compatibility with legacy web platform APIs\nand should never be used in new code, because they use strings to represent\nbinary data and predate the introduction of typed arrays in JavaScript.\nFor code running using Node.js APIs, converting between base64-encoded strings\nand binary data should be performed using Buffer.from(str, 'base64') and\nbuf.toString('base64').
Decodes a string into bytes using Latin-1 (ISO-8859), and encodes those bytes\ninto a string using Base64.
\nThe data may be any JavaScript-value that can be coerced into a string.
This function is only provided for compatibility with legacy web platform APIs\nand should never be used in new code, because they use strings to represent\nbinary data and predate the introduction of typed arrays in JavaScript.\nFor code running using Node.js APIs, converting between base64-encoded strings\nand binary data should be performed using Buffer.from(str, 'base64') and\nbuf.toString('base64').
Re-encodes the given Buffer or Uint8Array instance from one character\nencoding to another. Returns a new Buffer instance.
Throws if the fromEnc or toEnc specify invalid character encodings or if\nconversion from fromEnc to toEnc is not permitted.
Encodings supported by buffer.transcode() are: 'ascii', 'utf8',\n'utf16le', 'ucs2', 'latin1', and 'binary'.
The transcoding process will use substitution characters if a given byte\nsequence cannot be adequately represented in the target encoding. For instance:
\nimport { Buffer, transcode } from 'buffer';\n\nconst newBuf = transcode(Buffer.from('€'), 'utf8', 'ascii');\nconsole.log(newBuf.toString('ascii'));\n// Prints: '?'\nconst { Buffer, transcode } = require('buffer');\n\nconst newBuf = transcode(Buffer.from('€'), 'utf8', 'ascii');\nconsole.log(newBuf.toString('ascii'));\n// Prints: '?'\nBecause the Euro (€) sign is not representable in US-ASCII, it is replaced\nwith ? in the transcoded Buffer.
Returns the maximum number of bytes that will be returned when\nbuf.inspect() is called. This can be overridden by user modules. See\nutil.inspect() for more details on buf.inspect() behavior.
An alias for buffer.constants.MAX_LENGTH.
An alias for buffer.constants.MAX_STRING_LENGTH.
See Buffer.allocUnsafeSlow(). This was never a class in the sense that\nthe constructor always returned a Buffer instance, rather than a SlowBuffer\ninstance.
On 32-bit architectures, this value currently is 230 - 1 (about 1\nGB).
\nOn 64-bit architectures, this value currently is 232 (about 4 GB).
\nIt reflects v8::TypedArray::kMaxLength under the hood.
This value is also available as buffer.kMaxLength.
Represents the largest length that a string primitive can have, counted\nin UTF-16 code units.
This value may depend on the JS engine that is being used.
", "shortDesc": "The largest length allowed for a single `string` instance." } ], "type": "module", "displayName": "Buffer constants" } ], "type": "module", "displayName": "`buffer` module APIs" }, { "textRaw": "`Buffer.from()`, `Buffer.alloc()`, and `Buffer.allocUnsafe()`", "name": "`buffer.from()`,_`buffer.alloc()`,_and_`buffer.allocunsafe()`", "desc": "In versions of Node.js prior to 6.0.0, Buffer instances were created using the\nBuffer constructor function, which allocates the returned Buffer\ndifferently based on what arguments are provided:
Buffer() (e.g. new Buffer(10))\nallocates a new Buffer object of the specified size. Prior to Node.js 8.0.0,\nthe memory allocated for such Buffer instances is not initialized and\ncan contain sensitive data. Such Buffer instances must be subsequently\ninitialized by using either buf.fill(0) or by writing to the\nentire Buffer before reading data from the Buffer.\nWhile this behavior is intentional to improve performance,\ndevelopment experience has demonstrated that a more explicit distinction is\nrequired between creating a fast-but-uninitialized Buffer versus creating a\nslower-but-safer Buffer. Since Node.js 8.0.0, Buffer(num) and new Buffer(num) return a Buffer with initialized memory.Buffer as the first argument copies the\npassed object's data into the Buffer.ArrayBuffer or a SharedArrayBuffer returns a Buffer\nthat shares allocated memory with the given array buffer.Because the behavior of new Buffer() is different depending on the type of the\nfirst argument, security and reliability issues can be inadvertently introduced\ninto applications when argument validation or Buffer initialization is not\nperformed.
For example, if an attacker can cause an application to receive a number where\na string is expected, the application may call new Buffer(100)\ninstead of new Buffer(\"100\"), leading it to allocate a 100 byte buffer instead\nof allocating a 3 byte buffer with content \"100\". This is commonly possible\nusing JSON API calls. Since JSON distinguishes between numeric and string types,\nit allows injection of numbers where a naively written application that does not\nvalidate its input sufficiently might expect to always receive a string.\nBefore Node.js 8.0.0, the 100 byte buffer might contain\narbitrary pre-existing in-memory data, so may be used to expose in-memory\nsecrets to a remote attacker. Since Node.js 8.0.0, exposure of memory cannot\noccur because the data is zero-filled. However, other attacks are still\npossible, such as causing very large buffers to be allocated by the server,\nleading to performance degradation or crashing on memory exhaustion.
To make the creation of Buffer instances more reliable and less error-prone,\nthe various forms of the new Buffer() constructor have been deprecated\nand replaced by separate Buffer.from(), Buffer.alloc(), and\nBuffer.allocUnsafe() methods.
Developers should migrate all existing uses of the new Buffer() constructors\nto one of these new APIs.
Buffer.from(array) returns a new Buffer that contains a copy of the\nprovided octets.Buffer.from(arrayBuffer[, byteOffset[, length]])\nreturns a new Buffer that shares the same allocated memory as the given\nArrayBuffer.Buffer.from(buffer) returns a new Buffer that contains a copy of the\ncontents of the given Buffer.Buffer.from(string[, encoding]) returns a new\nBuffer that contains a copy of the provided string.Buffer.alloc(size[, fill[, encoding]]) returns a new\ninitialized Buffer of the specified size. This method is slower than\nBuffer.allocUnsafe(size) but guarantees that newly\ncreated Buffer instances never contain old data that is potentially\nsensitive. A TypeError will be thrown if size is not a number.Buffer.allocUnsafe(size) and\nBuffer.allocUnsafeSlow(size) each return a\nnew uninitialized Buffer of the specified size. Because the Buffer is\nuninitialized, the allocated segment of memory might contain old data that is\npotentially sensitive.Buffer instances returned by Buffer.allocUnsafe() and\nBuffer.from(array) may be allocated off a shared internal memory pool\nif size is less than or equal to half Buffer.poolSize. Instances\nreturned by Buffer.allocUnsafeSlow() never use the shared internal\nmemory pool.
Node.js can be started using the --zero-fill-buffers command-line option to\ncause all newly-allocated Buffer instances to be zero-filled upon creation by\ndefault. Without the option, buffers created with Buffer.allocUnsafe(),\nBuffer.allocUnsafeSlow(), and new SlowBuffer(size) are not zero-filled.\nUse of this flag can have a measurable negative impact on performance. Use the\n--zero-fill-buffers option only when necessary to enforce that newly allocated\nBuffer instances cannot contain old data that is potentially sensitive.
$ node --zero-fill-buffers\n> Buffer.allocUnsafe(5);\n<Buffer 00 00 00 00 00>\nWhen calling Buffer.allocUnsafe() and Buffer.allocUnsafeSlow(), the\nsegment of allocated memory is uninitialized (it is not zeroed-out). While\nthis design makes the allocation of memory quite fast, the allocated segment of\nmemory might contain old data that is potentially sensitive. Using a Buffer\ncreated by Buffer.allocUnsafe() without completely overwriting the\nmemory can allow this old data to be leaked when the Buffer memory is read.
While there are clear performance advantages to using\nBuffer.allocUnsafe(), extra care must be taken in order to avoid\nintroducing security vulnerabilities into an application.
A Blob encapsulates immutable, raw data that can be safely shared across\nmultiple worker threads.
Returns a promise that fulfills with an <ArrayBuffer> containing a copy of\nthe Blob data.
Creates and returns a new Blob containing a subset of this Blob objects\ndata. The original Blob is not altered.
Returns a promise that resolves the contents of the Blob decoded as a UTF-8\nstring.
The total size of the Blob in bytes.
The content-type of the Blob.
Once a <Blob> object is created, it can be sent via MessagePort to multiple\ndestinations without transferring or immediately copying the data. The data\ncontained by the Blob is copied only when the arrayBuffer() or text()\nmethods are called.
import { Blob, Buffer } from 'buffer';\nimport { setTimeout as delay } from 'timers/promises';\n\nconst blob = new Blob(['hello there']);\n\nconst mc1 = new MessageChannel();\nconst mc2 = new MessageChannel();\n\nmc1.port1.onmessage = async ({ data }) => {\n console.log(await data.arrayBuffer());\n mc1.port1.close();\n};\n\nmc2.port1.onmessage = async ({ data }) => {\n await delay(1000);\n console.log(await data.arrayBuffer());\n mc2.port1.close();\n};\n\nmc1.port2.postMessage(blob);\nmc2.port2.postMessage(blob);\n\n// The Blob is still usable after posting.\ndata.text().then(console.log);\nconst { Blob, Buffer } = require('buffer');\nconst { setTimeout: delay } = require('timers/promises');\n\nconst blob = new Blob(['hello there']);\n\nconst mc1 = new MessageChannel();\nconst mc2 = new MessageChannel();\n\nmc1.port1.onmessage = async ({ data }) => {\n console.log(await data.arrayBuffer());\n mc1.port1.close();\n};\n\nmc2.port1.onmessage = async ({ data }) => {\n await delay(1000);\n console.log(await data.arrayBuffer());\n mc2.port1.close();\n};\n\nmc1.port2.postMessage(blob);\nmc2.port2.postMessage(blob);\n\n// The Blob is still usable after posting.\ndata.text().then(console.log);\nCreates a new Blob object containing a concatenation of the given sources.
<ArrayBuffer>, <TypedArray>, <DataView>, and <Buffer> sources are copied into\nthe 'Blob' and can therefore be safely modified after the 'Blob' is created.
\nString sources are also copied into the Blob.
The Buffer class is a global type for dealing with binary data directly.\nIt can be constructed in a variety of ways.
Allocates a new Buffer of size bytes. If fill is undefined, the\nBuffer will be zero-filled.
import { Buffer } from 'buffer';\n\nconst buf = Buffer.alloc(5);\n\nconsole.log(buf);\n// Prints: <Buffer 00 00 00 00 00>\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.alloc(5);\n\nconsole.log(buf);\n// Prints: <Buffer 00 00 00 00 00>\nIf size is larger than\nbuffer.constants.MAX_LENGTH or smaller than 0, ERR_INVALID_ARG_VALUE\nis thrown.
If fill is specified, the allocated Buffer will be initialized by calling\nbuf.fill(fill).
import { Buffer } from 'buffer';\n\nconst buf = Buffer.alloc(5, 'a');\n\nconsole.log(buf);\n// Prints: <Buffer 61 61 61 61 61>\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.alloc(5, 'a');\n\nconsole.log(buf);\n// Prints: <Buffer 61 61 61 61 61>\nIf both fill and encoding are specified, the allocated Buffer will be\ninitialized by calling buf.fill(fill, encoding).
import { Buffer } from 'buffer';\n\nconst buf = Buffer.alloc(11, 'aGVsbG8gd29ybGQ=', 'base64');\n\nconsole.log(buf);\n// Prints: <Buffer 68 65 6c 6c 6f 20 77 6f 72 6c 64>\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.alloc(11, 'aGVsbG8gd29ybGQ=', 'base64');\n\nconsole.log(buf);\n// Prints: <Buffer 68 65 6c 6c 6f 20 77 6f 72 6c 64>\nCalling Buffer.alloc() can be measurably slower than the alternative\nBuffer.allocUnsafe() but ensures that the newly created Buffer instance\ncontents will never contain sensitive data from previous allocations, including\ndata that might not have been allocated for Buffers.
A TypeError will be thrown if size is not a number.
Allocates a new Buffer of size bytes. If size is larger than\nbuffer.constants.MAX_LENGTH or smaller than 0, ERR_INVALID_ARG_VALUE\nis thrown.
The underlying memory for Buffer instances created in this way is not\ninitialized. The contents of the newly created Buffer are unknown and\nmay contain sensitive data. Use Buffer.alloc() instead to initialize\nBuffer instances with zeroes.
import { Buffer } from 'buffer';\n\nconst buf = Buffer.allocUnsafe(10);\n\nconsole.log(buf);\n// Prints (contents may vary): <Buffer a0 8b 28 3f 01 00 00 00 50 32>\n\nbuf.fill(0);\n\nconsole.log(buf);\n// Prints: <Buffer 00 00 00 00 00 00 00 00 00 00>\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.allocUnsafe(10);\n\nconsole.log(buf);\n// Prints (contents may vary): <Buffer a0 8b 28 3f 01 00 00 00 50 32>\n\nbuf.fill(0);\n\nconsole.log(buf);\n// Prints: <Buffer 00 00 00 00 00 00 00 00 00 00>\nA TypeError will be thrown if size is not a number.
The Buffer module pre-allocates an internal Buffer instance of\nsize Buffer.poolSize that is used as a pool for the fast allocation of new\nBuffer instances created using Buffer.allocUnsafe(),\nBuffer.from(array), Buffer.concat(), and the deprecated\nnew Buffer(size) constructor only when size is less than or equal\nto Buffer.poolSize >> 1 (floor of Buffer.poolSize divided by two).
Use of this pre-allocated internal memory pool is a key difference between\ncalling Buffer.alloc(size, fill) vs. Buffer.allocUnsafe(size).fill(fill).\nSpecifically, Buffer.alloc(size, fill) will never use the internal Buffer\npool, while Buffer.allocUnsafe(size).fill(fill) will use the internal\nBuffer pool if size is less than or equal to half Buffer.poolSize. The\ndifference is subtle but can be important when an application requires the\nadditional performance that Buffer.allocUnsafe() provides.
Allocates a new Buffer of size bytes. If size is larger than\nbuffer.constants.MAX_LENGTH or smaller than 0, ERR_INVALID_ARG_VALUE\nis thrown. A zero-length Buffer is created if size is 0.
The underlying memory for Buffer instances created in this way is not\ninitialized. The contents of the newly created Buffer are unknown and\nmay contain sensitive data. Use buf.fill(0) to initialize\nsuch Buffer instances with zeroes.
When using Buffer.allocUnsafe() to allocate new Buffer instances,\nallocations under 4 KB are sliced from a single pre-allocated Buffer. This\nallows applications to avoid the garbage collection overhead of creating many\nindividually allocated Buffer instances. This approach improves both\nperformance and memory usage by eliminating the need to track and clean up as\nmany individual ArrayBuffer objects.
However, in the case where a developer may need to retain a small chunk of\nmemory from a pool for an indeterminate amount of time, it may be appropriate\nto create an un-pooled Buffer instance using Buffer.allocUnsafeSlow() and\nthen copying out the relevant bits.
import { Buffer } from 'buffer';\n\n// Need to keep around a few small chunks of memory.\nconst store = [];\n\nsocket.on('readable', () => {\n let data;\n while (null !== (data = readable.read())) {\n // Allocate for retained data.\n const sb = Buffer.allocUnsafeSlow(10);\n\n // Copy the data into the new allocation.\n data.copy(sb, 0, 0, 10);\n\n store.push(sb);\n }\n});\nconst { Buffer } = require('buffer');\n\n// Need to keep around a few small chunks of memory.\nconst store = [];\n\nsocket.on('readable', () => {\n let data;\n while (null !== (data = readable.read())) {\n // Allocate for retained data.\n const sb = Buffer.allocUnsafeSlow(10);\n\n // Copy the data into the new allocation.\n data.copy(sb, 0, 0, 10);\n\n store.push(sb);\n }\n});\nA TypeError will be thrown if size is not a number.
Returns the byte length of a string when encoded using encoding.\nThis is not the same as String.prototype.length, which does not account\nfor the encoding that is used to convert the string into bytes.
For 'base64', 'base64url', and 'hex', this function assumes valid input.\nFor strings that contain non-base64/hex-encoded data (e.g. whitespace), the\nreturn value might be greater than the length of a Buffer created from the\nstring.
import { Buffer } from 'buffer';\n\nconst str = '\\u00bd + \\u00bc = \\u00be';\n\nconsole.log(`${str}: ${str.length} characters, ` +\n `${Buffer.byteLength(str, 'utf8')} bytes`);\n// Prints: ½ + ¼ = ¾: 9 characters, 12 bytes\nconst { Buffer } = require('buffer');\n\nconst str = '\\u00bd + \\u00bc = \\u00be';\n\nconsole.log(`${str}: ${str.length} characters, ` +\n `${Buffer.byteLength(str, 'utf8')} bytes`);\n// Prints: ½ + ¼ = ¾: 9 characters, 12 bytes\nWhen string is a Buffer/DataView/TypedArray/ArrayBuffer/\nSharedArrayBuffer, the byte length as reported by .byteLength\nis returned.
Compares buf1 to buf2, typically for the purpose of sorting arrays of\nBuffer instances. This is equivalent to calling\nbuf1.compare(buf2).
import { Buffer } from 'buffer';\n\nconst buf1 = Buffer.from('1234');\nconst buf2 = Buffer.from('0123');\nconst arr = [buf1, buf2];\n\nconsole.log(arr.sort(Buffer.compare));\n// Prints: [ <Buffer 30 31 32 33>, <Buffer 31 32 33 34> ]\n// (This result is equal to: [buf2, buf1].)\nconst { Buffer } = require('buffer');\n\nconst buf1 = Buffer.from('1234');\nconst buf2 = Buffer.from('0123');\nconst arr = [buf1, buf2];\n\nconsole.log(arr.sort(Buffer.compare));\n// Prints: [ <Buffer 30 31 32 33>, <Buffer 31 32 33 34> ]\n// (This result is equal to: [buf2, buf1].)\nReturns a new Buffer which is the result of concatenating all the Buffer\ninstances in the list together.
If the list has no items, or if the totalLength is 0, then a new zero-length\nBuffer is returned.
If totalLength is not provided, it is calculated from the Buffer instances\nin list by adding their lengths.
If totalLength is provided, it is coerced to an unsigned integer. If the\ncombined length of the Buffers in list exceeds totalLength, the result is\ntruncated to totalLength.
import { Buffer } from 'buffer';\n\n// Create a single `Buffer` from a list of three `Buffer` instances.\n\nconst buf1 = Buffer.alloc(10);\nconst buf2 = Buffer.alloc(14);\nconst buf3 = Buffer.alloc(18);\nconst totalLength = buf1.length + buf2.length + buf3.length;\n\nconsole.log(totalLength);\n// Prints: 42\n\nconst bufA = Buffer.concat([buf1, buf2, buf3], totalLength);\n\nconsole.log(bufA);\n// Prints: <Buffer 00 00 00 00 ...>\nconsole.log(bufA.length);\n// Prints: 42\nconst { Buffer } = require('buffer');\n\n// Create a single `Buffer` from a list of three `Buffer` instances.\n\nconst buf1 = Buffer.alloc(10);\nconst buf2 = Buffer.alloc(14);\nconst buf3 = Buffer.alloc(18);\nconst totalLength = buf1.length + buf2.length + buf3.length;\n\nconsole.log(totalLength);\n// Prints: 42\n\nconst bufA = Buffer.concat([buf1, buf2, buf3], totalLength);\n\nconsole.log(bufA);\n// Prints: <Buffer 00 00 00 00 ...>\nconsole.log(bufA.length);\n// Prints: 42\nBuffer.concat() may also use the internal Buffer pool like\nBuffer.allocUnsafe() does.
Allocates a new Buffer using an array of bytes in the range 0 – 255.\nArray entries outside that range will be truncated to fit into it.
import { Buffer } from 'buffer';\n\n// Creates a new Buffer containing the UTF-8 bytes of the string 'buffer'.\nconst buf = Buffer.from([0x62, 0x75, 0x66, 0x66, 0x65, 0x72]);\nconst { Buffer } = require('buffer');\n\n// Creates a new Buffer containing the UTF-8 bytes of the string 'buffer'.\nconst buf = Buffer.from([0x62, 0x75, 0x66, 0x66, 0x65, 0x72]);\nA TypeError will be thrown if array is not an Array or another type\nappropriate for Buffer.from() variants.
Buffer.from(array) and Buffer.from(string) may also use the internal\nBuffer pool like Buffer.allocUnsafe() does.
This creates a view of the ArrayBuffer without copying the underlying\nmemory. For example, when passed a reference to the .buffer property of a\nTypedArray instance, the newly created Buffer will share the same\nallocated memory as the TypedArray's underlying ArrayBuffer.
import { Buffer } from 'buffer';\n\nconst arr = new Uint16Array(2);\n\narr[0] = 5000;\narr[1] = 4000;\n\n// Shares memory with `arr`.\nconst buf = Buffer.from(arr.buffer);\n\nconsole.log(buf);\n// Prints: <Buffer 88 13 a0 0f>\n\n// Changing the original Uint16Array changes the Buffer also.\narr[1] = 6000;\n\nconsole.log(buf);\n// Prints: <Buffer 88 13 70 17>\nconst { Buffer } = require('buffer');\n\nconst arr = new Uint16Array(2);\n\narr[0] = 5000;\narr[1] = 4000;\n\n// Shares memory with `arr`.\nconst buf = Buffer.from(arr.buffer);\n\nconsole.log(buf);\n// Prints: <Buffer 88 13 a0 0f>\n\n// Changing the original Uint16Array changes the Buffer also.\narr[1] = 6000;\n\nconsole.log(buf);\n// Prints: <Buffer 88 13 70 17>\nThe optional byteOffset and length arguments specify a memory range within\nthe arrayBuffer that will be shared by the Buffer.
import { Buffer } from 'buffer';\n\nconst ab = new ArrayBuffer(10);\nconst buf = Buffer.from(ab, 0, 2);\n\nconsole.log(buf.length);\n// Prints: 2\nconst { Buffer } = require('buffer');\n\nconst ab = new ArrayBuffer(10);\nconst buf = Buffer.from(ab, 0, 2);\n\nconsole.log(buf.length);\n// Prints: 2\nA TypeError will be thrown if arrayBuffer is not an ArrayBuffer or a\nSharedArrayBuffer or another type appropriate for Buffer.from()\nvariants.
It is important to remember that a backing ArrayBuffer can cover a range\nof memory that extends beyond the bounds of a TypedArray view. A new\nBuffer created using the buffer property of a TypedArray may extend\nbeyond the range of the TypedArray:
import { Buffer } from 'buffer';\n\nconst arrA = Uint8Array.from([0x63, 0x64, 0x65, 0x66]); // 4 elements\nconst arrB = new Uint8Array(arrA.buffer, 1, 2); // 2 elements\nconsole.log(arrA.buffer === arrB.buffer); // true\n\nconst buf = Buffer.from(arrB.buffer);\nconsole.log(buf);\n// Prints: <Buffer 63 64 65 66>\nconst { Buffer } = require('buffer');\n\nconst arrA = Uint8Array.from([0x63, 0x64, 0x65, 0x66]); // 4 elements\nconst arrB = new Uint8Array(arrA.buffer, 1, 2); // 2 elements\nconsole.log(arrA.buffer === arrB.buffer); // true\n\nconst buf = Buffer.from(arrB.buffer);\nconsole.log(buf);\n// Prints: <Buffer 63 64 65 66>\nCopies the passed buffer data onto a new Buffer instance.
import { Buffer } from 'buffer';\n\nconst buf1 = Buffer.from('buffer');\nconst buf2 = Buffer.from(buf1);\n\nbuf1[0] = 0x61;\n\nconsole.log(buf1.toString());\n// Prints: auffer\nconsole.log(buf2.toString());\n// Prints: buffer\nconst { Buffer } = require('buffer');\n\nconst buf1 = Buffer.from('buffer');\nconst buf2 = Buffer.from(buf1);\n\nbuf1[0] = 0x61;\n\nconsole.log(buf1.toString());\n// Prints: auffer\nconsole.log(buf2.toString());\n// Prints: buffer\nA TypeError will be thrown if buffer is not a Buffer or another type\nappropriate for Buffer.from() variants.
For objects whose valueOf() function returns a value not strictly equal to\nobject, returns Buffer.from(object.valueOf(), offsetOrEncoding, length).
import { Buffer } from 'buffer';\n\nconst buf = Buffer.from(new String('this is a test'));\n// Prints: <Buffer 74 68 69 73 20 69 73 20 61 20 74 65 73 74>\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.from(new String('this is a test'));\n// Prints: <Buffer 74 68 69 73 20 69 73 20 61 20 74 65 73 74>\nFor objects that support Symbol.toPrimitive, returns\nBuffer.from(object[Symbol.toPrimitive]('string'), offsetOrEncoding).
import { Buffer } from 'buffer';\n\nclass Foo {\n [Symbol.toPrimitive]() {\n return 'this is a test';\n }\n}\n\nconst buf = Buffer.from(new Foo(), 'utf8');\n// Prints: <Buffer 74 68 69 73 20 69 73 20 61 20 74 65 73 74>\nconst { Buffer } = require('buffer');\n\nclass Foo {\n [Symbol.toPrimitive]() {\n return 'this is a test';\n }\n}\n\nconst buf = Buffer.from(new Foo(), 'utf8');\n// Prints: <Buffer 74 68 69 73 20 69 73 20 61 20 74 65 73 74>\nA TypeError will be thrown if object does not have the mentioned methods or\nis not of another type appropriate for Buffer.from() variants.
Creates a new Buffer containing string. The encoding parameter identifies\nthe character encoding to be used when converting string into bytes.
import { Buffer } from 'buffer';\n\nconst buf1 = Buffer.from('this is a tést');\nconst buf2 = Buffer.from('7468697320697320612074c3a97374', 'hex');\n\nconsole.log(buf1.toString());\n// Prints: this is a tést\nconsole.log(buf2.toString());\n// Prints: this is a tést\nconsole.log(buf1.toString('latin1'));\n// Prints: this is a tést\nconst { Buffer } = require('buffer');\n\nconst buf1 = Buffer.from('this is a tést');\nconst buf2 = Buffer.from('7468697320697320612074c3a97374', 'hex');\n\nconsole.log(buf1.toString());\n// Prints: this is a tést\nconsole.log(buf2.toString());\n// Prints: this is a tést\nconsole.log(buf1.toString('latin1'));\n// Prints: this is a tést\nA TypeError will be thrown if string is not a string or another type\nappropriate for Buffer.from() variants.
Returns true if obj is a Buffer, false otherwise.
import { Buffer } from 'buffer';\n\nBuffer.isBuffer(Buffer.alloc(10)); // true\nBuffer.isBuffer(Buffer.from('foo')); // true\nBuffer.isBuffer('a string'); // false\nBuffer.isBuffer([]); // false\nBuffer.isBuffer(new Uint8Array(1024)); // false\nconst { Buffer } = require('buffer');\n\nBuffer.isBuffer(Buffer.alloc(10)); // true\nBuffer.isBuffer(Buffer.from('foo')); // true\nBuffer.isBuffer('a string'); // false\nBuffer.isBuffer([]); // false\nBuffer.isBuffer(new Uint8Array(1024)); // false\nReturns true if encoding is the name of a supported character encoding,\nor false otherwise.
import { Buffer } from 'buffer';\n\nconsole.log(Buffer.isEncoding('utf8'));\n// Prints: true\n\nconsole.log(Buffer.isEncoding('hex'));\n// Prints: true\n\nconsole.log(Buffer.isEncoding('utf/8'));\n// Prints: false\n\nconsole.log(Buffer.isEncoding(''));\n// Prints: false\nconst { Buffer } = require('buffer');\n\nconsole.log(Buffer.isEncoding('utf8'));\n// Prints: true\n\nconsole.log(Buffer.isEncoding('hex'));\n// Prints: true\n\nconsole.log(Buffer.isEncoding('utf/8'));\n// Prints: false\n\nconsole.log(Buffer.isEncoding(''));\n// Prints: false\nThis is the size (in bytes) of pre-allocated internal Buffer instances used\nfor pooling. This value may be modified.
The index operator [index] can be used to get and set the octet at position\nindex in buf. The values refer to individual bytes, so the legal value\nrange is between 0x00 and 0xFF (hex) or 0 and 255 (decimal).
This operator is inherited from Uint8Array, so its behavior on out-of-bounds\naccess is the same as Uint8Array. In other words, buf[index] returns\nundefined when index is negative or greater or equal to buf.length, and\nbuf[index] = value does not modify the buffer if index is negative or\n>= buf.length.
import { Buffer } from 'buffer';\n\n// Copy an ASCII string into a `Buffer` one byte at a time.\n// (This only works for ASCII-only strings. In general, one should use\n// `Buffer.from()` to perform this conversion.)\n\nconst str = 'Node.js';\nconst buf = Buffer.allocUnsafe(str.length);\n\nfor (let i = 0; i < str.length; i++) {\n buf[i] = str.charCodeAt(i);\n}\n\nconsole.log(buf.toString('utf8'));\n// Prints: Node.js\nconst { Buffer } = require('buffer');\n\n// Copy an ASCII string into a `Buffer` one byte at a time.\n// (This only works for ASCII-only strings. In general, one should use\n// `Buffer.from()` to perform this conversion.)\n\nconst str = 'Node.js';\nconst buf = Buffer.allocUnsafe(str.length);\n\nfor (let i = 0; i < str.length; i++) {\n buf[i] = str.charCodeAt(i);\n}\n\nconsole.log(buf.toString('utf8'));\n// Prints: Node.js\nThis ArrayBuffer is not guaranteed to correspond exactly to the original\nBuffer. See the notes on buf.byteOffset for details.
import { Buffer } from 'buffer';\n\nconst arrayBuffer = new ArrayBuffer(16);\nconst buffer = Buffer.from(arrayBuffer);\n\nconsole.log(buffer.buffer === arrayBuffer);\n// Prints: true\nconst { Buffer } = require('buffer');\n\nconst arrayBuffer = new ArrayBuffer(16);\nconst buffer = Buffer.from(arrayBuffer);\n\nconsole.log(buffer.buffer === arrayBuffer);\n// Prints: true\nWhen setting byteOffset in Buffer.from(ArrayBuffer, byteOffset, length),\nor sometimes when allocating a Buffer smaller than Buffer.poolSize, the\nbuffer does not start from a zero offset on the underlying ArrayBuffer.
This can cause problems when accessing the underlying ArrayBuffer directly\nusing buf.buffer, as other parts of the ArrayBuffer may be unrelated\nto the Buffer object itself.
A common issue when creating a TypedArray object that shares its memory with\na Buffer is that in this case one needs to specify the byteOffset correctly:
import { Buffer } from 'buffer';\n\n// Create a buffer smaller than `Buffer.poolSize`.\nconst nodeBuffer = new Buffer.from([0, 1, 2, 3, 4, 5, 6, 7, 8, 9]);\n\n// When casting the Node.js Buffer to an Int8Array, use the byteOffset\n// to refer only to the part of `nodeBuffer.buffer` that contains the memory\n// for `nodeBuffer`.\nnew Int8Array(nodeBuffer.buffer, nodeBuffer.byteOffset, nodeBuffer.length);\nconst { Buffer } = require('buffer');\n\n// Create a buffer smaller than `Buffer.poolSize`.\nconst nodeBuffer = new Buffer.from([0, 1, 2, 3, 4, 5, 6, 7, 8, 9]);\n\n// When casting the Node.js Buffer to an Int8Array, use the byteOffset\n// to refer only to the part of `nodeBuffer.buffer` that contains the memory\n// for `nodeBuffer`.\nnew Int8Array(nodeBuffer.buffer, nodeBuffer.byteOffset, nodeBuffer.length);\nReturns the number of bytes in buf.
import { Buffer } from 'buffer';\n\n// Create a `Buffer` and write a shorter string to it using UTF-8.\n\nconst buf = Buffer.alloc(1234);\n\nconsole.log(buf.length);\n// Prints: 1234\n\nbuf.write('some string', 0, 'utf8');\n\nconsole.log(buf.length);\n// Prints: 1234\nconst { Buffer } = require('buffer');\n\n// Create a `Buffer` and write a shorter string to it using UTF-8.\n\nconst buf = Buffer.alloc(1234);\n\nconsole.log(buf.length);\n// Prints: 1234\n\nbuf.write('some string', 0, 'utf8');\n\nconsole.log(buf.length);\n// Prints: 1234\nThe buf.parent property is a deprecated alias for buf.buffer.
Compares buf with target and returns a number indicating whether buf\ncomes before, after, or is the same as target in sort order.\nComparison is based on the actual sequence of bytes in each Buffer.
0 is returned if target is the same as buf1 is returned if target should come before buf when sorted.-1 is returned if target should come after buf when sorted.import { Buffer } from 'buffer';\n\nconst buf1 = Buffer.from('ABC');\nconst buf2 = Buffer.from('BCD');\nconst buf3 = Buffer.from('ABCD');\n\nconsole.log(buf1.compare(buf1));\n// Prints: 0\nconsole.log(buf1.compare(buf2));\n// Prints: -1\nconsole.log(buf1.compare(buf3));\n// Prints: -1\nconsole.log(buf2.compare(buf1));\n// Prints: 1\nconsole.log(buf2.compare(buf3));\n// Prints: 1\nconsole.log([buf1, buf2, buf3].sort(Buffer.compare));\n// Prints: [ <Buffer 41 42 43>, <Buffer 41 42 43 44>, <Buffer 42 43 44> ]\n// (This result is equal to: [buf1, buf3, buf2].)\nconst { Buffer } = require('buffer');\n\nconst buf1 = Buffer.from('ABC');\nconst buf2 = Buffer.from('BCD');\nconst buf3 = Buffer.from('ABCD');\n\nconsole.log(buf1.compare(buf1));\n// Prints: 0\nconsole.log(buf1.compare(buf2));\n// Prints: -1\nconsole.log(buf1.compare(buf3));\n// Prints: -1\nconsole.log(buf2.compare(buf1));\n// Prints: 1\nconsole.log(buf2.compare(buf3));\n// Prints: 1\nconsole.log([buf1, buf2, buf3].sort(Buffer.compare));\n// Prints: [ <Buffer 41 42 43>, <Buffer 41 42 43 44>, <Buffer 42 43 44> ]\n// (This result is equal to: [buf1, buf3, buf2].)\nThe optional targetStart, targetEnd, sourceStart, and sourceEnd\narguments can be used to limit the comparison to specific ranges within target\nand buf respectively.
import { Buffer } from 'buffer';\n\nconst buf1 = Buffer.from([1, 2, 3, 4, 5, 6, 7, 8, 9]);\nconst buf2 = Buffer.from([5, 6, 7, 8, 9, 1, 2, 3, 4]);\n\nconsole.log(buf1.compare(buf2, 5, 9, 0, 4));\n// Prints: 0\nconsole.log(buf1.compare(buf2, 0, 6, 4));\n// Prints: -1\nconsole.log(buf1.compare(buf2, 5, 6, 5));\n// Prints: 1\nconst { Buffer } = require('buffer');\n\nconst buf1 = Buffer.from([1, 2, 3, 4, 5, 6, 7, 8, 9]);\nconst buf2 = Buffer.from([5, 6, 7, 8, 9, 1, 2, 3, 4]);\n\nconsole.log(buf1.compare(buf2, 5, 9, 0, 4));\n// Prints: 0\nconsole.log(buf1.compare(buf2, 0, 6, 4));\n// Prints: -1\nconsole.log(buf1.compare(buf2, 5, 6, 5));\n// Prints: 1\nERR_OUT_OF_RANGE is thrown if targetStart < 0, sourceStart < 0,\ntargetEnd > target.byteLength, or sourceEnd > source.byteLength.
Copies data from a region of buf to a region in target, even if the target\nmemory region overlaps with buf.
TypedArray.prototype.set() performs the same operation, and is available\nfor all TypedArrays, including Node.js Buffers, although it takes\ndifferent function arguments.
import { Buffer } from 'buffer';\n\n// Create two `Buffer` instances.\nconst buf1 = Buffer.allocUnsafe(26);\nconst buf2 = Buffer.allocUnsafe(26).fill('!');\n\nfor (let i = 0; i < 26; i++) {\n // 97 is the decimal ASCII value for 'a'.\n buf1[i] = i + 97;\n}\n\n// Copy `buf1` bytes 16 through 19 into `buf2` starting at byte 8 of `buf2`.\nbuf1.copy(buf2, 8, 16, 20);\n// This is equivalent to:\n// buf2.set(buf1.subarray(16, 20), 8);\n\nconsole.log(buf2.toString('ascii', 0, 25));\n// Prints: !!!!!!!!qrst!!!!!!!!!!!!!\nconst { Buffer } = require('buffer');\n\n// Create two `Buffer` instances.\nconst buf1 = Buffer.allocUnsafe(26);\nconst buf2 = Buffer.allocUnsafe(26).fill('!');\n\nfor (let i = 0; i < 26; i++) {\n // 97 is the decimal ASCII value for 'a'.\n buf1[i] = i + 97;\n}\n\n// Copy `buf1` bytes 16 through 19 into `buf2` starting at byte 8 of `buf2`.\nbuf1.copy(buf2, 8, 16, 20);\n// This is equivalent to:\n// buf2.set(buf1.subarray(16, 20), 8);\n\nconsole.log(buf2.toString('ascii', 0, 25));\n// Prints: !!!!!!!!qrst!!!!!!!!!!!!!\nimport { Buffer } from 'buffer';\n\n// Create a `Buffer` and copy data from one region to an overlapping region\n// within the same `Buffer`.\n\nconst buf = Buffer.allocUnsafe(26);\n\nfor (let i = 0; i < 26; i++) {\n // 97 is the decimal ASCII value for 'a'.\n buf[i] = i + 97;\n}\n\nbuf.copy(buf, 0, 4, 10);\n\nconsole.log(buf.toString());\n// Prints: efghijghijklmnopqrstuvwxyz\nconst { Buffer } = require('buffer');\n\n// Create a `Buffer` and copy data from one region to an overlapping region\n// within the same `Buffer`.\n\nconst buf = Buffer.allocUnsafe(26);\n\nfor (let i = 0; i < 26; i++) {\n // 97 is the decimal ASCII value for 'a'.\n buf[i] = i + 97;\n}\n\nbuf.copy(buf, 0, 4, 10);\n\nconsole.log(buf.toString());\n// Prints: efghijghijklmnopqrstuvwxyz\nCreates and returns an iterator of [index, byte] pairs from the contents\nof buf.
import { Buffer } from 'buffer';\n\n// Log the entire contents of a `Buffer`.\n\nconst buf = Buffer.from('buffer');\n\nfor (const pair of buf.entries()) {\n console.log(pair);\n}\n// Prints:\n// [0, 98]\n// [1, 117]\n// [2, 102]\n// [3, 102]\n// [4, 101]\n// [5, 114]\nconst { Buffer } = require('buffer');\n\n// Log the entire contents of a `Buffer`.\n\nconst buf = Buffer.from('buffer');\n\nfor (const pair of buf.entries()) {\n console.log(pair);\n}\n// Prints:\n// [0, 98]\n// [1, 117]\n// [2, 102]\n// [3, 102]\n// [4, 101]\n// [5, 114]\nReturns true if both buf and otherBuffer have exactly the same bytes,\nfalse otherwise. Equivalent to\nbuf.compare(otherBuffer) === 0.
import { Buffer } from 'buffer';\n\nconst buf1 = Buffer.from('ABC');\nconst buf2 = Buffer.from('414243', 'hex');\nconst buf3 = Buffer.from('ABCD');\n\nconsole.log(buf1.equals(buf2));\n// Prints: true\nconsole.log(buf1.equals(buf3));\n// Prints: false\nconst { Buffer } = require('buffer');\n\nconst buf1 = Buffer.from('ABC');\nconst buf2 = Buffer.from('414243', 'hex');\nconst buf3 = Buffer.from('ABCD');\n\nconsole.log(buf1.equals(buf2));\n// Prints: true\nconsole.log(buf1.equals(buf3));\n// Prints: false\nFills buf with the specified value. If the offset and end are not given,\nthe entire buf will be filled:
import { Buffer } from 'buffer';\n\n// Fill a `Buffer` with the ASCII character 'h'.\n\nconst b = Buffer.allocUnsafe(50).fill('h');\n\nconsole.log(b.toString());\n// Prints: hhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh\nconst { Buffer } = require('buffer');\n\n// Fill a `Buffer` with the ASCII character 'h'.\n\nconst b = Buffer.allocUnsafe(50).fill('h');\n\nconsole.log(b.toString());\n// Prints: hhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh\nvalue is coerced to a uint32 value if it is not a string, Buffer, or\ninteger. If the resulting integer is greater than 255 (decimal), buf will be\nfilled with value & 255.
If the final write of a fill() operation falls on a multi-byte character,\nthen only the bytes of that character that fit into buf are written:
import { Buffer } from 'buffer';\n\n// Fill a `Buffer` with character that takes up two bytes in UTF-8.\n\nconsole.log(Buffer.allocUnsafe(5).fill('\\u0222'));\n// Prints: <Buffer c8 a2 c8 a2 c8>\nconst { Buffer } = require('buffer');\n\n// Fill a `Buffer` with character that takes up two bytes in UTF-8.\n\nconsole.log(Buffer.allocUnsafe(5).fill('\\u0222'));\n// Prints: <Buffer c8 a2 c8 a2 c8>\nIf value contains invalid characters, it is truncated; if no valid\nfill data remains, an exception is thrown:
import { Buffer } from 'buffer';\n\nconst buf = Buffer.allocUnsafe(5);\n\nconsole.log(buf.fill('a'));\n// Prints: <Buffer 61 61 61 61 61>\nconsole.log(buf.fill('aazz', 'hex'));\n// Prints: <Buffer aa aa aa aa aa>\nconsole.log(buf.fill('zz', 'hex'));\n// Throws an exception.\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.allocUnsafe(5);\n\nconsole.log(buf.fill('a'));\n// Prints: <Buffer 61 61 61 61 61>\nconsole.log(buf.fill('aazz', 'hex'));\n// Prints: <Buffer aa aa aa aa aa>\nconsole.log(buf.fill('zz', 'hex'));\n// Throws an exception.\nEquivalent to buf.indexOf() !== -1.
import { Buffer } from 'buffer';\n\nconst buf = Buffer.from('this is a buffer');\n\nconsole.log(buf.includes('this'));\n// Prints: true\nconsole.log(buf.includes('is'));\n// Prints: true\nconsole.log(buf.includes(Buffer.from('a buffer')));\n// Prints: true\nconsole.log(buf.includes(97));\n// Prints: true (97 is the decimal ASCII value for 'a')\nconsole.log(buf.includes(Buffer.from('a buffer example')));\n// Prints: false\nconsole.log(buf.includes(Buffer.from('a buffer example').slice(0, 8)));\n// Prints: true\nconsole.log(buf.includes('this', 4));\n// Prints: false\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.from('this is a buffer');\n\nconsole.log(buf.includes('this'));\n// Prints: true\nconsole.log(buf.includes('is'));\n// Prints: true\nconsole.log(buf.includes(Buffer.from('a buffer')));\n// Prints: true\nconsole.log(buf.includes(97));\n// Prints: true (97 is the decimal ASCII value for 'a')\nconsole.log(buf.includes(Buffer.from('a buffer example')));\n// Prints: false\nconsole.log(buf.includes(Buffer.from('a buffer example').slice(0, 8)));\n// Prints: true\nconsole.log(buf.includes('this', 4));\n// Prints: false\nIf value is:
value is interpreted according to the character encoding in\nencoding.Buffer or Uint8Array, value will be used in its entirety.\nTo compare a partial Buffer, use buf.slice().value will be interpreted as an unsigned 8-bit integer\nvalue between 0 and 255.import { Buffer } from 'buffer';\n\nconst buf = Buffer.from('this is a buffer');\n\nconsole.log(buf.indexOf('this'));\n// Prints: 0\nconsole.log(buf.indexOf('is'));\n// Prints: 2\nconsole.log(buf.indexOf(Buffer.from('a buffer')));\n// Prints: 8\nconsole.log(buf.indexOf(97));\n// Prints: 8 (97 is the decimal ASCII value for 'a')\nconsole.log(buf.indexOf(Buffer.from('a buffer example')));\n// Prints: -1\nconsole.log(buf.indexOf(Buffer.from('a buffer example').slice(0, 8)));\n// Prints: 8\n\nconst utf16Buffer = Buffer.from('\\u039a\\u0391\\u03a3\\u03a3\\u0395', 'utf16le');\n\nconsole.log(utf16Buffer.indexOf('\\u03a3', 0, 'utf16le'));\n// Prints: 4\nconsole.log(utf16Buffer.indexOf('\\u03a3', -4, 'utf16le'));\n// Prints: 6\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.from('this is a buffer');\n\nconsole.log(buf.indexOf('this'));\n// Prints: 0\nconsole.log(buf.indexOf('is'));\n// Prints: 2\nconsole.log(buf.indexOf(Buffer.from('a buffer')));\n// Prints: 8\nconsole.log(buf.indexOf(97));\n// Prints: 8 (97 is the decimal ASCII value for 'a')\nconsole.log(buf.indexOf(Buffer.from('a buffer example')));\n// Prints: -1\nconsole.log(buf.indexOf(Buffer.from('a buffer example').slice(0, 8)));\n// Prints: 8\n\nconst utf16Buffer = Buffer.from('\\u039a\\u0391\\u03a3\\u03a3\\u0395', 'utf16le');\n\nconsole.log(utf16Buffer.indexOf('\\u03a3', 0, 'utf16le'));\n// Prints: 4\nconsole.log(utf16Buffer.indexOf('\\u03a3', -4, 'utf16le'));\n// Prints: 6\nIf value is not a string, number, or Buffer, this method will throw a\nTypeError. If value is a number, it will be coerced to a valid byte value,\nan integer between 0 and 255.
If byteOffset is not a number, it will be coerced to a number. If the result\nof coercion is NaN or 0, then the entire buffer will be searched. This\nbehavior matches String.prototype.indexOf().
import { Buffer } from 'buffer';\n\nconst b = Buffer.from('abcdef');\n\n// Passing a value that's a number, but not a valid byte.\n// Prints: 2, equivalent to searching for 99 or 'c'.\nconsole.log(b.indexOf(99.9));\nconsole.log(b.indexOf(256 + 99));\n\n// Passing a byteOffset that coerces to NaN or 0.\n// Prints: 1, searching the whole buffer.\nconsole.log(b.indexOf('b', undefined));\nconsole.log(b.indexOf('b', {}));\nconsole.log(b.indexOf('b', null));\nconsole.log(b.indexOf('b', []));\nconst { Buffer } = require('buffer');\n\nconst b = Buffer.from('abcdef');\n\n// Passing a value that's a number, but not a valid byte.\n// Prints: 2, equivalent to searching for 99 or 'c'.\nconsole.log(b.indexOf(99.9));\nconsole.log(b.indexOf(256 + 99));\n\n// Passing a byteOffset that coerces to NaN or 0.\n// Prints: 1, searching the whole buffer.\nconsole.log(b.indexOf('b', undefined));\nconsole.log(b.indexOf('b', {}));\nconsole.log(b.indexOf('b', null));\nconsole.log(b.indexOf('b', []));\nIf value is an empty string or empty Buffer and byteOffset is less\nthan buf.length, byteOffset will be returned. If value is empty and\nbyteOffset is at least buf.length, buf.length will be returned.
Creates and returns an iterator of buf keys (indices).
import { Buffer } from 'buffer';\n\nconst buf = Buffer.from('buffer');\n\nfor (const key of buf.keys()) {\n console.log(key);\n}\n// Prints:\n// 0\n// 1\n// 2\n// 3\n// 4\n// 5\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.from('buffer');\n\nfor (const key of buf.keys()) {\n console.log(key);\n}\n// Prints:\n// 0\n// 1\n// 2\n// 3\n// 4\n// 5\nIdentical to buf.indexOf(), except the last occurrence of value is found\nrather than the first occurrence.
import { Buffer } from 'buffer';\n\nconst buf = Buffer.from('this buffer is a buffer');\n\nconsole.log(buf.lastIndexOf('this'));\n// Prints: 0\nconsole.log(buf.lastIndexOf('buffer'));\n// Prints: 17\nconsole.log(buf.lastIndexOf(Buffer.from('buffer')));\n// Prints: 17\nconsole.log(buf.lastIndexOf(97));\n// Prints: 15 (97 is the decimal ASCII value for 'a')\nconsole.log(buf.lastIndexOf(Buffer.from('yolo')));\n// Prints: -1\nconsole.log(buf.lastIndexOf('buffer', 5));\n// Prints: 5\nconsole.log(buf.lastIndexOf('buffer', 4));\n// Prints: -1\n\nconst utf16Buffer = Buffer.from('\\u039a\\u0391\\u03a3\\u03a3\\u0395', 'utf16le');\n\nconsole.log(utf16Buffer.lastIndexOf('\\u03a3', undefined, 'utf16le'));\n// Prints: 6\nconsole.log(utf16Buffer.lastIndexOf('\\u03a3', -5, 'utf16le'));\n// Prints: 4\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.from('this buffer is a buffer');\n\nconsole.log(buf.lastIndexOf('this'));\n// Prints: 0\nconsole.log(buf.lastIndexOf('buffer'));\n// Prints: 17\nconsole.log(buf.lastIndexOf(Buffer.from('buffer')));\n// Prints: 17\nconsole.log(buf.lastIndexOf(97));\n// Prints: 15 (97 is the decimal ASCII value for 'a')\nconsole.log(buf.lastIndexOf(Buffer.from('yolo')));\n// Prints: -1\nconsole.log(buf.lastIndexOf('buffer', 5));\n// Prints: 5\nconsole.log(buf.lastIndexOf('buffer', 4));\n// Prints: -1\n\nconst utf16Buffer = Buffer.from('\\u039a\\u0391\\u03a3\\u03a3\\u0395', 'utf16le');\n\nconsole.log(utf16Buffer.lastIndexOf('\\u03a3', undefined, 'utf16le'));\n// Prints: 6\nconsole.log(utf16Buffer.lastIndexOf('\\u03a3', -5, 'utf16le'));\n// Prints: 4\nIf value is not a string, number, or Buffer, this method will throw a\nTypeError. If value is a number, it will be coerced to a valid byte value,\nan integer between 0 and 255.
If byteOffset is not a number, it will be coerced to a number. Any arguments\nthat coerce to NaN, like {} or undefined, will search the whole buffer.\nThis behavior matches String.prototype.lastIndexOf().
import { Buffer } from 'buffer';\n\nconst b = Buffer.from('abcdef');\n\n// Passing a value that's a number, but not a valid byte.\n// Prints: 2, equivalent to searching for 99 or 'c'.\nconsole.log(b.lastIndexOf(99.9));\nconsole.log(b.lastIndexOf(256 + 99));\n\n// Passing a byteOffset that coerces to NaN.\n// Prints: 1, searching the whole buffer.\nconsole.log(b.lastIndexOf('b', undefined));\nconsole.log(b.lastIndexOf('b', {}));\n\n// Passing a byteOffset that coerces to 0.\n// Prints: -1, equivalent to passing 0.\nconsole.log(b.lastIndexOf('b', null));\nconsole.log(b.lastIndexOf('b', []));\nconst { Buffer } = require('buffer');\n\nconst b = Buffer.from('abcdef');\n\n// Passing a value that's a number, but not a valid byte.\n// Prints: 2, equivalent to searching for 99 or 'c'.\nconsole.log(b.lastIndexOf(99.9));\nconsole.log(b.lastIndexOf(256 + 99));\n\n// Passing a byteOffset that coerces to NaN.\n// Prints: 1, searching the whole buffer.\nconsole.log(b.lastIndexOf('b', undefined));\nconsole.log(b.lastIndexOf('b', {}));\n\n// Passing a byteOffset that coerces to 0.\n// Prints: -1, equivalent to passing 0.\nconsole.log(b.lastIndexOf('b', null));\nconsole.log(b.lastIndexOf('b', []));\nIf value is an empty string or empty Buffer, byteOffset will be returned.
Reads a signed, big-endian 64-bit integer from buf at the specified offset.
Integers read from a Buffer are interpreted as two's complement signed\nvalues.
Reads a signed, little-endian 64-bit integer from buf at the specified\noffset.
Integers read from a Buffer are interpreted as two's complement signed\nvalues.
Reads an unsigned, big-endian 64-bit integer from buf at the specified\noffset.
This function is also available under the readBigUint64BE alias.
import { Buffer } from 'buffer';\n\nconst buf = Buffer.from([0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff]);\n\nconsole.log(buf.readBigUInt64BE(0));\n// Prints: 4294967295n\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.from([0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff]);\n\nconsole.log(buf.readBigUInt64BE(0));\n// Prints: 4294967295n\nReads an unsigned, little-endian 64-bit integer from buf at the specified\noffset.
This function is also available under the readBigUint64LE alias.
import { Buffer } from 'buffer';\n\nconst buf = Buffer.from([0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff]);\n\nconsole.log(buf.readBigUInt64LE(0));\n// Prints: 18446744069414584320n\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.from([0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff]);\n\nconsole.log(buf.readBigUInt64LE(0));\n// Prints: 18446744069414584320n\nReads a 64-bit, big-endian double from buf at the specified offset.
import { Buffer } from 'buffer';\n\nconst buf = Buffer.from([1, 2, 3, 4, 5, 6, 7, 8]);\n\nconsole.log(buf.readDoubleBE(0));\n// Prints: 8.20788039913184e-304\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.from([1, 2, 3, 4, 5, 6, 7, 8]);\n\nconsole.log(buf.readDoubleBE(0));\n// Prints: 8.20788039913184e-304\nReads a 64-bit, little-endian double from buf at the specified offset.
import { Buffer } from 'buffer';\n\nconst buf = Buffer.from([1, 2, 3, 4, 5, 6, 7, 8]);\n\nconsole.log(buf.readDoubleLE(0));\n// Prints: 5.447603722011605e-270\nconsole.log(buf.readDoubleLE(1));\n// Throws ERR_OUT_OF_RANGE.\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.from([1, 2, 3, 4, 5, 6, 7, 8]);\n\nconsole.log(buf.readDoubleLE(0));\n// Prints: 5.447603722011605e-270\nconsole.log(buf.readDoubleLE(1));\n// Throws ERR_OUT_OF_RANGE.\nReads a 32-bit, big-endian float from buf at the specified offset.
import { Buffer } from 'buffer';\n\nconst buf = Buffer.from([1, 2, 3, 4]);\n\nconsole.log(buf.readFloatBE(0));\n// Prints: 2.387939260590663e-38\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.from([1, 2, 3, 4]);\n\nconsole.log(buf.readFloatBE(0));\n// Prints: 2.387939260590663e-38\nReads a 32-bit, little-endian float from buf at the specified offset.
import { Buffer } from 'buffer';\n\nconst buf = Buffer.from([1, 2, 3, 4]);\n\nconsole.log(buf.readFloatLE(0));\n// Prints: 1.539989614439558e-36\nconsole.log(buf.readFloatLE(1));\n// Throws ERR_OUT_OF_RANGE.\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.from([1, 2, 3, 4]);\n\nconsole.log(buf.readFloatLE(0));\n// Prints: 1.539989614439558e-36\nconsole.log(buf.readFloatLE(1));\n// Throws ERR_OUT_OF_RANGE.\nReads a signed 8-bit integer from buf at the specified offset.
Integers read from a Buffer are interpreted as two's complement signed values.
import { Buffer } from 'buffer';\n\nconst buf = Buffer.from([-1, 5]);\n\nconsole.log(buf.readInt8(0));\n// Prints: -1\nconsole.log(buf.readInt8(1));\n// Prints: 5\nconsole.log(buf.readInt8(2));\n// Throws ERR_OUT_OF_RANGE.\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.from([-1, 5]);\n\nconsole.log(buf.readInt8(0));\n// Prints: -1\nconsole.log(buf.readInt8(1));\n// Prints: 5\nconsole.log(buf.readInt8(2));\n// Throws ERR_OUT_OF_RANGE.\nReads a signed, big-endian 16-bit integer from buf at the specified offset.
Integers read from a Buffer are interpreted as two's complement signed values.
import { Buffer } from 'buffer';\n\nconst buf = Buffer.from([0, 5]);\n\nconsole.log(buf.readInt16BE(0));\n// Prints: 5\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.from([0, 5]);\n\nconsole.log(buf.readInt16BE(0));\n// Prints: 5\nReads a signed, little-endian 16-bit integer from buf at the specified\noffset.
Integers read from a Buffer are interpreted as two's complement signed values.
import { Buffer } from 'buffer';\n\nconst buf = Buffer.from([0, 5]);\n\nconsole.log(buf.readInt16LE(0));\n// Prints: 1280\nconsole.log(buf.readInt16LE(1));\n// Throws ERR_OUT_OF_RANGE.\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.from([0, 5]);\n\nconsole.log(buf.readInt16LE(0));\n// Prints: 1280\nconsole.log(buf.readInt16LE(1));\n// Throws ERR_OUT_OF_RANGE.\nReads a signed, big-endian 32-bit integer from buf at the specified offset.
Integers read from a Buffer are interpreted as two's complement signed values.
import { Buffer } from 'buffer';\n\nconst buf = Buffer.from([0, 0, 0, 5]);\n\nconsole.log(buf.readInt32BE(0));\n// Prints: 5\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.from([0, 0, 0, 5]);\n\nconsole.log(buf.readInt32BE(0));\n// Prints: 5\nReads a signed, little-endian 32-bit integer from buf at the specified\noffset.
Integers read from a Buffer are interpreted as two's complement signed values.
import { Buffer } from 'buffer';\n\nconst buf = Buffer.from([0, 0, 0, 5]);\n\nconsole.log(buf.readInt32LE(0));\n// Prints: 83886080\nconsole.log(buf.readInt32LE(1));\n// Throws ERR_OUT_OF_RANGE.\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.from([0, 0, 0, 5]);\n\nconsole.log(buf.readInt32LE(0));\n// Prints: 83886080\nconsole.log(buf.readInt32LE(1));\n// Throws ERR_OUT_OF_RANGE.\nReads byteLength number of bytes from buf at the specified offset\nand interprets the result as a big-endian, two's complement signed value\nsupporting up to 48 bits of accuracy.
import { Buffer } from 'buffer';\n\nconst buf = Buffer.from([0x12, 0x34, 0x56, 0x78, 0x90, 0xab]);\n\nconsole.log(buf.readIntBE(0, 6).toString(16));\n// Prints: 1234567890ab\nconsole.log(buf.readIntBE(1, 6).toString(16));\n// Throws ERR_OUT_OF_RANGE.\nconsole.log(buf.readIntBE(1, 0).toString(16));\n// Throws ERR_OUT_OF_RANGE.\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.from([0x12, 0x34, 0x56, 0x78, 0x90, 0xab]);\n\nconsole.log(buf.readIntBE(0, 6).toString(16));\n// Prints: 1234567890ab\nconsole.log(buf.readIntBE(1, 6).toString(16));\n// Throws ERR_OUT_OF_RANGE.\nconsole.log(buf.readIntBE(1, 0).toString(16));\n// Throws ERR_OUT_OF_RANGE.\nReads byteLength number of bytes from buf at the specified offset\nand interprets the result as a little-endian, two's complement signed value\nsupporting up to 48 bits of accuracy.
import { Buffer } from 'buffer';\n\nconst buf = Buffer.from([0x12, 0x34, 0x56, 0x78, 0x90, 0xab]);\n\nconsole.log(buf.readIntLE(0, 6).toString(16));\n// Prints: -546f87a9cbee\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.from([0x12, 0x34, 0x56, 0x78, 0x90, 0xab]);\n\nconsole.log(buf.readIntLE(0, 6).toString(16));\n// Prints: -546f87a9cbee\nReads an unsigned 8-bit integer from buf at the specified offset.
This function is also available under the readUint8 alias.
import { Buffer } from 'buffer';\n\nconst buf = Buffer.from([1, -2]);\n\nconsole.log(buf.readUInt8(0));\n// Prints: 1\nconsole.log(buf.readUInt8(1));\n// Prints: 254\nconsole.log(buf.readUInt8(2));\n// Throws ERR_OUT_OF_RANGE.\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.from([1, -2]);\n\nconsole.log(buf.readUInt8(0));\n// Prints: 1\nconsole.log(buf.readUInt8(1));\n// Prints: 254\nconsole.log(buf.readUInt8(2));\n// Throws ERR_OUT_OF_RANGE.\nReads an unsigned, big-endian 16-bit integer from buf at the specified\noffset.
This function is also available under the readUint16BE alias.
import { Buffer } from 'buffer';\n\nconst buf = Buffer.from([0x12, 0x34, 0x56]);\n\nconsole.log(buf.readUInt16BE(0).toString(16));\n// Prints: 1234\nconsole.log(buf.readUInt16BE(1).toString(16));\n// Prints: 3456\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.from([0x12, 0x34, 0x56]);\n\nconsole.log(buf.readUInt16BE(0).toString(16));\n// Prints: 1234\nconsole.log(buf.readUInt16BE(1).toString(16));\n// Prints: 3456\nReads an unsigned, little-endian 16-bit integer from buf at the specified\noffset.
This function is also available under the readUint16LE alias.
import { Buffer } from 'buffer';\n\nconst buf = Buffer.from([0x12, 0x34, 0x56]);\n\nconsole.log(buf.readUInt16LE(0).toString(16));\n// Prints: 3412\nconsole.log(buf.readUInt16LE(1).toString(16));\n// Prints: 5634\nconsole.log(buf.readUInt16LE(2).toString(16));\n// Throws ERR_OUT_OF_RANGE.\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.from([0x12, 0x34, 0x56]);\n\nconsole.log(buf.readUInt16LE(0).toString(16));\n// Prints: 3412\nconsole.log(buf.readUInt16LE(1).toString(16));\n// Prints: 5634\nconsole.log(buf.readUInt16LE(2).toString(16));\n// Throws ERR_OUT_OF_RANGE.\nReads an unsigned, big-endian 32-bit integer from buf at the specified\noffset.
This function is also available under the readUint32BE alias.
import { Buffer } from 'buffer';\n\nconst buf = Buffer.from([0x12, 0x34, 0x56, 0x78]);\n\nconsole.log(buf.readUInt32BE(0).toString(16));\n// Prints: 12345678\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.from([0x12, 0x34, 0x56, 0x78]);\n\nconsole.log(buf.readUInt32BE(0).toString(16));\n// Prints: 12345678\nReads an unsigned, little-endian 32-bit integer from buf at the specified\noffset.
This function is also available under the readUint32LE alias.
import { Buffer } from 'buffer';\n\nconst buf = Buffer.from([0x12, 0x34, 0x56, 0x78]);\n\nconsole.log(buf.readUInt32LE(0).toString(16));\n// Prints: 78563412\nconsole.log(buf.readUInt32LE(1).toString(16));\n// Throws ERR_OUT_OF_RANGE.\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.from([0x12, 0x34, 0x56, 0x78]);\n\nconsole.log(buf.readUInt32LE(0).toString(16));\n// Prints: 78563412\nconsole.log(buf.readUInt32LE(1).toString(16));\n// Throws ERR_OUT_OF_RANGE.\nReads byteLength number of bytes from buf at the specified offset\nand interprets the result as an unsigned big-endian integer supporting\nup to 48 bits of accuracy.
This function is also available under the readUintBE alias.
import { Buffer } from 'buffer';\n\nconst buf = Buffer.from([0x12, 0x34, 0x56, 0x78, 0x90, 0xab]);\n\nconsole.log(buf.readUIntBE(0, 6).toString(16));\n// Prints: 1234567890ab\nconsole.log(buf.readUIntBE(1, 6).toString(16));\n// Throws ERR_OUT_OF_RANGE.\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.from([0x12, 0x34, 0x56, 0x78, 0x90, 0xab]);\n\nconsole.log(buf.readUIntBE(0, 6).toString(16));\n// Prints: 1234567890ab\nconsole.log(buf.readUIntBE(1, 6).toString(16));\n// Throws ERR_OUT_OF_RANGE.\nReads byteLength number of bytes from buf at the specified offset\nand interprets the result as an unsigned, little-endian integer supporting\nup to 48 bits of accuracy.
This function is also available under the readUintLE alias.
import { Buffer } from 'buffer';\n\nconst buf = Buffer.from([0x12, 0x34, 0x56, 0x78, 0x90, 0xab]);\n\nconsole.log(buf.readUIntLE(0, 6).toString(16));\n// Prints: ab9078563412\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.from([0x12, 0x34, 0x56, 0x78, 0x90, 0xab]);\n\nconsole.log(buf.readUIntLE(0, 6).toString(16));\n// Prints: ab9078563412\nReturns a new Buffer that references the same memory as the original, but\noffset and cropped by the start and end indices.
Specifying end greater than buf.length will return the same result as\nthat of end equal to buf.length.
This method is inherited from TypedArray.prototype.subarray().
Modifying the new Buffer slice will modify the memory in the original Buffer\nbecause the allocated memory of the two objects overlap.
import { Buffer } from 'buffer';\n\n// Create a `Buffer` with the ASCII alphabet, take a slice, and modify one byte\n// from the original `Buffer`.\n\nconst buf1 = Buffer.allocUnsafe(26);\n\nfor (let i = 0; i < 26; i++) {\n // 97 is the decimal ASCII value for 'a'.\n buf1[i] = i + 97;\n}\n\nconst buf2 = buf1.subarray(0, 3);\n\nconsole.log(buf2.toString('ascii', 0, buf2.length));\n// Prints: abc\n\nbuf1[0] = 33;\n\nconsole.log(buf2.toString('ascii', 0, buf2.length));\n// Prints: !bc\nconst { Buffer } = require('buffer');\n\n// Create a `Buffer` with the ASCII alphabet, take a slice, and modify one byte\n// from the original `Buffer`.\n\nconst buf1 = Buffer.allocUnsafe(26);\n\nfor (let i = 0; i < 26; i++) {\n // 97 is the decimal ASCII value for 'a'.\n buf1[i] = i + 97;\n}\n\nconst buf2 = buf1.subarray(0, 3);\n\nconsole.log(buf2.toString('ascii', 0, buf2.length));\n// Prints: abc\n\nbuf1[0] = 33;\n\nconsole.log(buf2.toString('ascii', 0, buf2.length));\n// Prints: !bc\nSpecifying negative indexes causes the slice to be generated relative to the\nend of buf rather than the beginning.
import { Buffer } from 'buffer';\n\nconst buf = Buffer.from('buffer');\n\nconsole.log(buf.subarray(-6, -1).toString());\n// Prints: buffe\n// (Equivalent to buf.subarray(0, 5).)\n\nconsole.log(buf.subarray(-6, -2).toString());\n// Prints: buff\n// (Equivalent to buf.subarray(0, 4).)\n\nconsole.log(buf.subarray(-5, -2).toString());\n// Prints: uff\n// (Equivalent to buf.subarray(1, 4).)\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.from('buffer');\n\nconsole.log(buf.subarray(-6, -1).toString());\n// Prints: buffe\n// (Equivalent to buf.subarray(0, 5).)\n\nconsole.log(buf.subarray(-6, -2).toString());\n// Prints: buff\n// (Equivalent to buf.subarray(0, 4).)\n\nconsole.log(buf.subarray(-5, -2).toString());\n// Prints: uff\n// (Equivalent to buf.subarray(1, 4).)\nReturns a new Buffer that references the same memory as the original, but\noffset and cropped by the start and end indices.
This is the same behavior as buf.subarray().
This method is not compatible with the Uint8Array.prototype.slice(),\nwhich is a superclass of Buffer. To copy the slice, use\nUint8Array.prototype.slice().
import { Buffer } from 'buffer';\n\nconst buf = Buffer.from('buffer');\n\nconst copiedBuf = Uint8Array.prototype.slice.call(buf);\ncopiedBuf[0]++;\nconsole.log(copiedBuf.toString());\n// Prints: cuffer\n\nconsole.log(buf.toString());\n// Prints: buffer\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.from('buffer');\n\nconst copiedBuf = Uint8Array.prototype.slice.call(buf);\ncopiedBuf[0]++;\nconsole.log(copiedBuf.toString());\n// Prints: cuffer\n\nconsole.log(buf.toString());\n// Prints: buffer\nInterprets buf as an array of unsigned 16-bit integers and swaps the\nbyte order in-place. Throws ERR_INVALID_BUFFER_SIZE if buf.length\nis not a multiple of 2.
import { Buffer } from 'buffer';\n\nconst buf1 = Buffer.from([0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8]);\n\nconsole.log(buf1);\n// Prints: <Buffer 01 02 03 04 05 06 07 08>\n\nbuf1.swap16();\n\nconsole.log(buf1);\n// Prints: <Buffer 02 01 04 03 06 05 08 07>\n\nconst buf2 = Buffer.from([0x1, 0x2, 0x3]);\n\nbuf2.swap16();\n// Throws ERR_INVALID_BUFFER_SIZE.\nconst { Buffer } = require('buffer');\n\nconst buf1 = Buffer.from([0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8]);\n\nconsole.log(buf1);\n// Prints: <Buffer 01 02 03 04 05 06 07 08>\n\nbuf1.swap16();\n\nconsole.log(buf1);\n// Prints: <Buffer 02 01 04 03 06 05 08 07>\n\nconst buf2 = Buffer.from([0x1, 0x2, 0x3]);\n\nbuf2.swap16();\n// Throws ERR_INVALID_BUFFER_SIZE.\nOne convenient use of buf.swap16() is to perform a fast in-place conversion\nbetween UTF-16 little-endian and UTF-16 big-endian:
import { Buffer } from 'buffer';\n\nconst buf = Buffer.from('This is little-endian UTF-16', 'utf16le');\nbuf.swap16(); // Convert to big-endian UTF-16 text.\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.from('This is little-endian UTF-16', 'utf16le');\nbuf.swap16(); // Convert to big-endian UTF-16 text.\nInterprets buf as an array of unsigned 32-bit integers and swaps the\nbyte order in-place. Throws ERR_INVALID_BUFFER_SIZE if buf.length\nis not a multiple of 4.
import { Buffer } from 'buffer';\n\nconst buf1 = Buffer.from([0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8]);\n\nconsole.log(buf1);\n// Prints: <Buffer 01 02 03 04 05 06 07 08>\n\nbuf1.swap32();\n\nconsole.log(buf1);\n// Prints: <Buffer 04 03 02 01 08 07 06 05>\n\nconst buf2 = Buffer.from([0x1, 0x2, 0x3]);\n\nbuf2.swap32();\n// Throws ERR_INVALID_BUFFER_SIZE.\nconst { Buffer } = require('buffer');\n\nconst buf1 = Buffer.from([0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8]);\n\nconsole.log(buf1);\n// Prints: <Buffer 01 02 03 04 05 06 07 08>\n\nbuf1.swap32();\n\nconsole.log(buf1);\n// Prints: <Buffer 04 03 02 01 08 07 06 05>\n\nconst buf2 = Buffer.from([0x1, 0x2, 0x3]);\n\nbuf2.swap32();\n// Throws ERR_INVALID_BUFFER_SIZE.\nInterprets buf as an array of 64-bit numbers and swaps byte order in-place.\nThrows ERR_INVALID_BUFFER_SIZE if buf.length is not a multiple of 8.
import { Buffer } from 'buffer';\n\nconst buf1 = Buffer.from([0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8]);\n\nconsole.log(buf1);\n// Prints: <Buffer 01 02 03 04 05 06 07 08>\n\nbuf1.swap64();\n\nconsole.log(buf1);\n// Prints: <Buffer 08 07 06 05 04 03 02 01>\n\nconst buf2 = Buffer.from([0x1, 0x2, 0x3]);\n\nbuf2.swap64();\n// Throws ERR_INVALID_BUFFER_SIZE.\nconst { Buffer } = require('buffer');\n\nconst buf1 = Buffer.from([0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8]);\n\nconsole.log(buf1);\n// Prints: <Buffer 01 02 03 04 05 06 07 08>\n\nbuf1.swap64();\n\nconsole.log(buf1);\n// Prints: <Buffer 08 07 06 05 04 03 02 01>\n\nconst buf2 = Buffer.from([0x1, 0x2, 0x3]);\n\nbuf2.swap64();\n// Throws ERR_INVALID_BUFFER_SIZE.\nReturns a JSON representation of buf. JSON.stringify() implicitly calls\nthis function when stringifying a Buffer instance.
Buffer.from() accepts objects in the format returned from this method.\nIn particular, Buffer.from(buf.toJSON()) works like Buffer.from(buf).
import { Buffer } from 'buffer';\n\nconst buf = Buffer.from([0x1, 0x2, 0x3, 0x4, 0x5]);\nconst json = JSON.stringify(buf);\n\nconsole.log(json);\n// Prints: {\"type\":\"Buffer\",\"data\":[1,2,3,4,5]}\n\nconst copy = JSON.parse(json, (key, value) => {\n return value && value.type === 'Buffer' ?\n Buffer.from(value) :\n value;\n});\n\nconsole.log(copy);\n// Prints: <Buffer 01 02 03 04 05>\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.from([0x1, 0x2, 0x3, 0x4, 0x5]);\nconst json = JSON.stringify(buf);\n\nconsole.log(json);\n// Prints: {\"type\":\"Buffer\",\"data\":[1,2,3,4,5]}\n\nconst copy = JSON.parse(json, (key, value) => {\n return value && value.type === 'Buffer' ?\n Buffer.from(value) :\n value;\n});\n\nconsole.log(copy);\n// Prints: <Buffer 01 02 03 04 05>\nDecodes buf to a string according to the specified character encoding in\nencoding. start and end may be passed to decode only a subset of buf.
If encoding is 'utf8' and a byte sequence in the input is not valid UTF-8,\nthen each invalid byte is replaced with the replacement character U+FFFD.
The maximum length of a string instance (in UTF-16 code units) is available\nas buffer.constants.MAX_STRING_LENGTH.
import { Buffer } from 'buffer';\n\nconst buf1 = Buffer.allocUnsafe(26);\n\nfor (let i = 0; i < 26; i++) {\n // 97 is the decimal ASCII value for 'a'.\n buf1[i] = i + 97;\n}\n\nconsole.log(buf1.toString('utf8'));\n// Prints: abcdefghijklmnopqrstuvwxyz\nconsole.log(buf1.toString('utf8', 0, 5));\n// Prints: abcde\n\nconst buf2 = Buffer.from('tést');\n\nconsole.log(buf2.toString('hex'));\n// Prints: 74c3a97374\nconsole.log(buf2.toString('utf8', 0, 3));\n// Prints: té\nconsole.log(buf2.toString(undefined, 0, 3));\n// Prints: té\nconst { Buffer } = require('buffer');\n\nconst buf1 = Buffer.allocUnsafe(26);\n\nfor (let i = 0; i < 26; i++) {\n // 97 is the decimal ASCII value for 'a'.\n buf1[i] = i + 97;\n}\n\nconsole.log(buf1.toString('utf8'));\n// Prints: abcdefghijklmnopqrstuvwxyz\nconsole.log(buf1.toString('utf8', 0, 5));\n// Prints: abcde\n\nconst buf2 = Buffer.from('tést');\n\nconsole.log(buf2.toString('hex'));\n// Prints: 74c3a97374\nconsole.log(buf2.toString('utf8', 0, 3));\n// Prints: té\nconsole.log(buf2.toString(undefined, 0, 3));\n// Prints: té\nCreates and returns an iterator for buf values (bytes). This function is\ncalled automatically when a Buffer is used in a for..of statement.
import { Buffer } from 'buffer';\n\nconst buf = Buffer.from('buffer');\n\nfor (const value of buf.values()) {\n console.log(value);\n}\n// Prints:\n// 98\n// 117\n// 102\n// 102\n// 101\n// 114\n\nfor (const value of buf) {\n console.log(value);\n}\n// Prints:\n// 98\n// 117\n// 102\n// 102\n// 101\n// 114\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.from('buffer');\n\nfor (const value of buf.values()) {\n console.log(value);\n}\n// Prints:\n// 98\n// 117\n// 102\n// 102\n// 101\n// 114\n\nfor (const value of buf) {\n console.log(value);\n}\n// Prints:\n// 98\n// 117\n// 102\n// 102\n// 101\n// 114\nWrites string to buf at offset according to the character encoding in\nencoding. The length parameter is the number of bytes to write. If buf did\nnot contain enough space to fit the entire string, only part of string will be\nwritten. However, partially encoded characters will not be written.
import { Buffer } from 'buffer';\n\nconst buf = Buffer.alloc(256);\n\nconst len = buf.write('\\u00bd + \\u00bc = \\u00be', 0);\n\nconsole.log(`${len} bytes: ${buf.toString('utf8', 0, len)}`);\n// Prints: 12 bytes: ½ + ¼ = ¾\n\nconst buffer = Buffer.alloc(10);\n\nconst length = buffer.write('abcd', 8);\n\nconsole.log(`${length} bytes: ${buffer.toString('utf8', 8, 10)}`);\n// Prints: 2 bytes : ab\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.alloc(256);\n\nconst len = buf.write('\\u00bd + \\u00bc = \\u00be', 0);\n\nconsole.log(`${len} bytes: ${buf.toString('utf8', 0, len)}`);\n// Prints: 12 bytes: ½ + ¼ = ¾\n\nconst buffer = Buffer.alloc(10);\n\nconst length = buffer.write('abcd', 8);\n\nconsole.log(`${length} bytes: ${buffer.toString('utf8', 8, 10)}`);\n// Prints: 2 bytes : ab\nWrites value to buf at the specified offset as big-endian.
value is interpreted and written as a two's complement signed integer.
import { Buffer } from 'buffer';\n\nconst buf = Buffer.allocUnsafe(8);\n\nbuf.writeBigInt64BE(0x0102030405060708n, 0);\n\nconsole.log(buf);\n// Prints: <Buffer 01 02 03 04 05 06 07 08>\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.allocUnsafe(8);\n\nbuf.writeBigInt64BE(0x0102030405060708n, 0);\n\nconsole.log(buf);\n// Prints: <Buffer 01 02 03 04 05 06 07 08>\nWrites value to buf at the specified offset as little-endian.
value is interpreted and written as a two's complement signed integer.
import { Buffer } from 'buffer';\n\nconst buf = Buffer.allocUnsafe(8);\n\nbuf.writeBigInt64LE(0x0102030405060708n, 0);\n\nconsole.log(buf);\n// Prints: <Buffer 08 07 06 05 04 03 02 01>\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.allocUnsafe(8);\n\nbuf.writeBigInt64LE(0x0102030405060708n, 0);\n\nconsole.log(buf);\n// Prints: <Buffer 08 07 06 05 04 03 02 01>\nWrites value to buf at the specified offset as big-endian.
This function is also available under the writeBigUint64BE alias.
import { Buffer } from 'buffer';\n\nconst buf = Buffer.allocUnsafe(8);\n\nbuf.writeBigUInt64BE(0xdecafafecacefaden, 0);\n\nconsole.log(buf);\n// Prints: <Buffer de ca fa fe ca ce fa de>\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.allocUnsafe(8);\n\nbuf.writeBigUInt64BE(0xdecafafecacefaden, 0);\n\nconsole.log(buf);\n// Prints: <Buffer de ca fa fe ca ce fa de>\nWrites value to buf at the specified offset as little-endian
import { Buffer } from 'buffer';\n\nconst buf = Buffer.allocUnsafe(8);\n\nbuf.writeBigUInt64LE(0xdecafafecacefaden, 0);\n\nconsole.log(buf);\n// Prints: <Buffer de fa ce ca fe fa ca de>\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.allocUnsafe(8);\n\nbuf.writeBigUInt64LE(0xdecafafecacefaden, 0);\n\nconsole.log(buf);\n// Prints: <Buffer de fa ce ca fe fa ca de>\nThis function is also available under the writeBigUint64LE alias.
Writes value to buf at the specified offset as big-endian. The value\nmust be a JavaScript number. Behavior is undefined when value is anything\nother than a JavaScript number.
import { Buffer } from 'buffer';\n\nconst buf = Buffer.allocUnsafe(8);\n\nbuf.writeDoubleBE(123.456, 0);\n\nconsole.log(buf);\n// Prints: <Buffer 40 5e dd 2f 1a 9f be 77>\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.allocUnsafe(8);\n\nbuf.writeDoubleBE(123.456, 0);\n\nconsole.log(buf);\n// Prints: <Buffer 40 5e dd 2f 1a 9f be 77>\nWrites value to buf at the specified offset as little-endian. The value\nmust be a JavaScript number. Behavior is undefined when value is anything\nother than a JavaScript number.
import { Buffer } from 'buffer';\n\nconst buf = Buffer.allocUnsafe(8);\n\nbuf.writeDoubleLE(123.456, 0);\n\nconsole.log(buf);\n// Prints: <Buffer 77 be 9f 1a 2f dd 5e 40>\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.allocUnsafe(8);\n\nbuf.writeDoubleLE(123.456, 0);\n\nconsole.log(buf);\n// Prints: <Buffer 77 be 9f 1a 2f dd 5e 40>\nWrites value to buf at the specified offset as big-endian. Behavior is\nundefined when value is anything other than a JavaScript number.
import { Buffer } from 'buffer';\n\nconst buf = Buffer.allocUnsafe(4);\n\nbuf.writeFloatBE(0xcafebabe, 0);\n\nconsole.log(buf);\n// Prints: <Buffer 4f 4a fe bb>\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.allocUnsafe(4);\n\nbuf.writeFloatBE(0xcafebabe, 0);\n\nconsole.log(buf);\n// Prints: <Buffer 4f 4a fe bb>\nWrites value to buf at the specified offset as little-endian. Behavior is\nundefined when value is anything other than a JavaScript number.
import { Buffer } from 'buffer';\n\nconst buf = Buffer.allocUnsafe(4);\n\nbuf.writeFloatLE(0xcafebabe, 0);\n\nconsole.log(buf);\n// Prints: <Buffer bb fe 4a 4f>\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.allocUnsafe(4);\n\nbuf.writeFloatLE(0xcafebabe, 0);\n\nconsole.log(buf);\n// Prints: <Buffer bb fe 4a 4f>\nWrites value to buf at the specified offset. value must be a valid\nsigned 8-bit integer. Behavior is undefined when value is anything other than\na signed 8-bit integer.
value is interpreted and written as a two's complement signed integer.
import { Buffer } from 'buffer';\n\nconst buf = Buffer.allocUnsafe(2);\n\nbuf.writeInt8(2, 0);\nbuf.writeInt8(-2, 1);\n\nconsole.log(buf);\n// Prints: <Buffer 02 fe>\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.allocUnsafe(2);\n\nbuf.writeInt8(2, 0);\nbuf.writeInt8(-2, 1);\n\nconsole.log(buf);\n// Prints: <Buffer 02 fe>\nWrites value to buf at the specified offset as big-endian. The value\nmust be a valid signed 16-bit integer. Behavior is undefined when value is\nanything other than a signed 16-bit integer.
The value is interpreted and written as a two's complement signed integer.
import { Buffer } from 'buffer';\n\nconst buf = Buffer.allocUnsafe(2);\n\nbuf.writeInt16BE(0x0102, 0);\n\nconsole.log(buf);\n// Prints: <Buffer 01 02>\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.allocUnsafe(2);\n\nbuf.writeInt16BE(0x0102, 0);\n\nconsole.log(buf);\n// Prints: <Buffer 01 02>\nWrites value to buf at the specified offset as little-endian. The value\nmust be a valid signed 16-bit integer. Behavior is undefined when value is\nanything other than a signed 16-bit integer.
The value is interpreted and written as a two's complement signed integer.
import { Buffer } from 'buffer';\n\nconst buf = Buffer.allocUnsafe(2);\n\nbuf.writeInt16LE(0x0304, 0);\n\nconsole.log(buf);\n// Prints: <Buffer 04 03>\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.allocUnsafe(2);\n\nbuf.writeInt16LE(0x0304, 0);\n\nconsole.log(buf);\n// Prints: <Buffer 04 03>\nWrites value to buf at the specified offset as big-endian. The value\nmust be a valid signed 32-bit integer. Behavior is undefined when value is\nanything other than a signed 32-bit integer.
The value is interpreted and written as a two's complement signed integer.
import { Buffer } from 'buffer';\n\nconst buf = Buffer.allocUnsafe(4);\n\nbuf.writeInt32BE(0x01020304, 0);\n\nconsole.log(buf);\n// Prints: <Buffer 01 02 03 04>\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.allocUnsafe(4);\n\nbuf.writeInt32BE(0x01020304, 0);\n\nconsole.log(buf);\n// Prints: <Buffer 01 02 03 04>\nWrites value to buf at the specified offset as little-endian. The value\nmust be a valid signed 32-bit integer. Behavior is undefined when value is\nanything other than a signed 32-bit integer.
The value is interpreted and written as a two's complement signed integer.
import { Buffer } from 'buffer';\n\nconst buf = Buffer.allocUnsafe(4);\n\nbuf.writeInt32LE(0x05060708, 0);\n\nconsole.log(buf);\n// Prints: <Buffer 08 07 06 05>\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.allocUnsafe(4);\n\nbuf.writeInt32LE(0x05060708, 0);\n\nconsole.log(buf);\n// Prints: <Buffer 08 07 06 05>\nWrites byteLength bytes of value to buf at the specified offset\nas big-endian. Supports up to 48 bits of accuracy. Behavior is undefined when\nvalue is anything other than a signed integer.
import { Buffer } from 'buffer';\n\nconst buf = Buffer.allocUnsafe(6);\n\nbuf.writeIntBE(0x1234567890ab, 0, 6);\n\nconsole.log(buf);\n// Prints: <Buffer 12 34 56 78 90 ab>\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.allocUnsafe(6);\n\nbuf.writeIntBE(0x1234567890ab, 0, 6);\n\nconsole.log(buf);\n// Prints: <Buffer 12 34 56 78 90 ab>\nWrites byteLength bytes of value to buf at the specified offset\nas little-endian. Supports up to 48 bits of accuracy. Behavior is undefined\nwhen value is anything other than a signed integer.
import { Buffer } from 'buffer';\n\nconst buf = Buffer.allocUnsafe(6);\n\nbuf.writeIntLE(0x1234567890ab, 0, 6);\n\nconsole.log(buf);\n// Prints: <Buffer ab 90 78 56 34 12>\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.allocUnsafe(6);\n\nbuf.writeIntLE(0x1234567890ab, 0, 6);\n\nconsole.log(buf);\n// Prints: <Buffer ab 90 78 56 34 12>\nWrites value to buf at the specified offset. value must be a\nvalid unsigned 8-bit integer. Behavior is undefined when value is anything\nother than an unsigned 8-bit integer.
This function is also available under the writeUint8 alias.
import { Buffer } from 'buffer';\n\nconst buf = Buffer.allocUnsafe(4);\n\nbuf.writeUInt8(0x3, 0);\nbuf.writeUInt8(0x4, 1);\nbuf.writeUInt8(0x23, 2);\nbuf.writeUInt8(0x42, 3);\n\nconsole.log(buf);\n// Prints: <Buffer 03 04 23 42>\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.allocUnsafe(4);\n\nbuf.writeUInt8(0x3, 0);\nbuf.writeUInt8(0x4, 1);\nbuf.writeUInt8(0x23, 2);\nbuf.writeUInt8(0x42, 3);\n\nconsole.log(buf);\n// Prints: <Buffer 03 04 23 42>\nWrites value to buf at the specified offset as big-endian. The value\nmust be a valid unsigned 16-bit integer. Behavior is undefined when value\nis anything other than an unsigned 16-bit integer.
This function is also available under the writeUint16BE alias.
import { Buffer } from 'buffer';\n\nconst buf = Buffer.allocUnsafe(4);\n\nbuf.writeUInt16BE(0xdead, 0);\nbuf.writeUInt16BE(0xbeef, 2);\n\nconsole.log(buf);\n// Prints: <Buffer de ad be ef>\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.allocUnsafe(4);\n\nbuf.writeUInt16BE(0xdead, 0);\nbuf.writeUInt16BE(0xbeef, 2);\n\nconsole.log(buf);\n// Prints: <Buffer de ad be ef>\nWrites value to buf at the specified offset as little-endian. The value\nmust be a valid unsigned 16-bit integer. Behavior is undefined when value is\nanything other than an unsigned 16-bit integer.
This function is also available under the writeUint16LE alias.
import { Buffer } from 'buffer';\n\nconst buf = Buffer.allocUnsafe(4);\n\nbuf.writeUInt16LE(0xdead, 0);\nbuf.writeUInt16LE(0xbeef, 2);\n\nconsole.log(buf);\n// Prints: <Buffer ad de ef be>\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.allocUnsafe(4);\n\nbuf.writeUInt16LE(0xdead, 0);\nbuf.writeUInt16LE(0xbeef, 2);\n\nconsole.log(buf);\n// Prints: <Buffer ad de ef be>\nWrites value to buf at the specified offset as big-endian. The value\nmust be a valid unsigned 32-bit integer. Behavior is undefined when value\nis anything other than an unsigned 32-bit integer.
This function is also available under the writeUint32BE alias.
import { Buffer } from 'buffer';\n\nconst buf = Buffer.allocUnsafe(4);\n\nbuf.writeUInt32BE(0xfeedface, 0);\n\nconsole.log(buf);\n// Prints: <Buffer fe ed fa ce>\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.allocUnsafe(4);\n\nbuf.writeUInt32BE(0xfeedface, 0);\n\nconsole.log(buf);\n// Prints: <Buffer fe ed fa ce>\nWrites value to buf at the specified offset as little-endian. The value\nmust be a valid unsigned 32-bit integer. Behavior is undefined when value is\nanything other than an unsigned 32-bit integer.
This function is also available under the writeUint32LE alias.
import { Buffer } from 'buffer';\n\nconst buf = Buffer.allocUnsafe(4);\n\nbuf.writeUInt32LE(0xfeedface, 0);\n\nconsole.log(buf);\n// Prints: <Buffer ce fa ed fe>\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.allocUnsafe(4);\n\nbuf.writeUInt32LE(0xfeedface, 0);\n\nconsole.log(buf);\n// Prints: <Buffer ce fa ed fe>\nWrites byteLength bytes of value to buf at the specified offset\nas big-endian. Supports up to 48 bits of accuracy. Behavior is undefined\nwhen value is anything other than an unsigned integer.
This function is also available under the writeUintBE alias.
import { Buffer } from 'buffer';\n\nconst buf = Buffer.allocUnsafe(6);\n\nbuf.writeUIntBE(0x1234567890ab, 0, 6);\n\nconsole.log(buf);\n// Prints: <Buffer 12 34 56 78 90 ab>\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.allocUnsafe(6);\n\nbuf.writeUIntBE(0x1234567890ab, 0, 6);\n\nconsole.log(buf);\n// Prints: <Buffer 12 34 56 78 90 ab>\nWrites byteLength bytes of value to buf at the specified offset\nas little-endian. Supports up to 48 bits of accuracy. Behavior is undefined\nwhen value is anything other than an unsigned integer.
This function is also available under the writeUintLE alias.
import { Buffer } from 'buffer';\n\nconst buf = Buffer.allocUnsafe(6);\n\nbuf.writeUIntLE(0x1234567890ab, 0, 6);\n\nconsole.log(buf);\n// Prints: <Buffer ab 90 78 56 34 12>\nconst { Buffer } = require('buffer');\n\nconst buf = Buffer.allocUnsafe(6);\n\nbuf.writeUIntLE(0x1234567890ab, 0, 6);\n\nconsole.log(buf);\n// Prints: <Buffer ab 90 78 56 34 12>\nSee Buffer.from(array).
See\nBuffer.from(arrayBuffer[, byteOffset[, length]]).
See Buffer.from(buffer).
See Buffer.alloc() and Buffer.allocUnsafe(). This variant of the\nconstructor is equivalent to Buffer.alloc().