Prior to the introduction of TypedArray in ECMAScript 2015 (ES6), the\nJavaScript language had no mechanism for reading or manipulating streams\nof binary data. The Buffer class was introduced as part of the Node.js\nAPI to make it possible to interact with octet streams in the context of things\nlike TCP streams and file system operations.
Now that TypedArray has been added in ES6, the Buffer class implements the\nUint8Array API in a manner that is more optimized and suitable for Node.js'\nuse cases.
Instances of the Buffer class are similar to arrays of integers but\ncorrespond to fixed-sized, raw memory allocations outside the V8 heap.\nThe size of the Buffer is established when it is created and cannot be\nresized.
The Buffer class is a global within Node.js, making it unlikely that one\nwould need to ever use require('buffer').Buffer.
const buf1 = Buffer.alloc(10);\n // Creates a zero-filled Buffer of length 10.\n\nconst buf2 = Buffer.alloc(10, 1);\n // Creates a Buffer of length 10, filled with 0x01.\n\nconst buf3 = Buffer.allocUnsafe(10);\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 either fill() or write().\n\nconst buf4 = Buffer.from([1,2,3]);\n // Creates a Buffer containing [01, 02, 03].\n\nconst buf5 = Buffer.from('test');\n // Creates a Buffer containing ASCII bytes [74, 65, 73, 74].\n\nconst buf6 = Buffer.from('tést', 'utf8');\n // Creates a Buffer containing UTF8 bytes [74, c3, a9, 73, 74].\nIn versions of Node.js prior to v6, 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. The memory allocated\nfor such Buffer instances is not initialized and can contain sensitive\ndata. Such Buffer objects must be initialized manually by using either\n[buf.fill(0)][] or by writing to the Buffer completely. While this\nbehavior is intentional to improve performance, development experience has\ndemonstrated that a more explicit distinction is required between creating a\nfast-but-uninitialized Buffer versus creating a slower-but-safer Buffer.Buffer as the first argument copies the\npassed object's data into the Buffer.ArrayBuffer returns a Buffer that shares allocated memory with\nthe given ArrayBuffer.Because the behavior of new Buffer() changes significantly based on the type\nof value passed as the first argument, applications that do not properly\nvalidate the input arguments passed to new Buffer(), or that fail to\nappropriately initialize newly allocated Buffer content, can inadvertently\nintroduce security and reliability issues into their code.
To make the creation of Buffer objects 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)][buffer_from_array] returns a new Buffer containing\na copy of the provided octets.Buffer.from(arrayBuffer[, byteOffset [, length]])][buffer_from_arraybuf]\nreturns a new Buffer that shares the same allocated memory as the given\nArrayBuffer.Buffer.from(buffer)][buffer_from_buffer] returns a new Buffer\ncontaining a copy of the contents of the given Buffer.Buffer.from(str[, encoding])][buffer_from_string] returns a new Buffer\ncontaining a copy of the provided string.Buffer.alloc(size[, fill[, encoding]])][buffer_alloc] returns a "filled"\nBuffer instance of the specified size. This method can be significantly\nslower than [Buffer.allocUnsafe(size)][buffer_allocunsafe] but ensures\nthat newly created Buffer instances never contain old and potentially\nsensitive data.Buffer.allocUnsafe(size)][buffer_allocunsafe] and\n[Buffer.allocUnsafeSlow(size)][buffer_allocunsafeslow] each return a\nnew Buffer of the specified size whose content must be initialized\nusing either [buf.fill(0)][] or written to completely.Buffer instances returned by Buffer.allocUnsafe(size) may be allocated\noff a shared internal memory pool if size is less than or equal to half\nBuffer.poolSize. Instances returned by Buffer.allocUnsafeSlow(size) never\nuse the shared internal memory pool.
Node.js can be started using the --zero-fill-buffers command line option to\nforce all newly allocated Buffer instances created using either\nnew Buffer(size), Buffer.allocUnsafe(size), Buffer.allocUnsafeSlow(size)\nor new SlowBuffer(size) to be automatically zero-filled upon creation. Use\nof this flag changes the default behavior of these methods and can have a\nsignificant impact on performance. Use of the --zero-fill-buffers option is\nrecommended only when absolutely necessary to enforce that newly allocated\nBuffer instances cannot contain potentially sensitive data.
$ 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 memory\ncan allow this old data to be leaked when the Buffer memory is read.
While there are clear performance advantages to using Buffer.allocUnsafe(),\nextra care must be taken in order to avoid introducing security\nvulnerabilities into an application.
Buffers are commonly used to represent sequences of encoded characters\nsuch as UTF8, UCS2, Base64 or even Hex-encoded data. It is possible to\nconvert back and forth between Buffers and ordinary JavaScript string objects\nby using an explicit encoding method.
\nconst buf = Buffer.from('hello world', 'ascii');\nconsole.log(buf.toString('hex'));\n // prints: 68656c6c6f20776f726c64\nconsole.log(buf.toString('base64'));\n // prints: aGVsbG8gd29ybGQ=\nThe character encodings currently supported by Node.js include:
\n'ascii' - for 7-bit ASCII data only. This encoding method is very fast and\nwill strip the high bit if set.
'utf8' - Multibyte encoded Unicode characters. Many web pages and other\ndocument formats use UTF-8.
'utf16le' - 2 or 4 bytes, little-endian encoded Unicode characters.\nSurrogate pairs (U+10000 to U+10FFFF) are supported.
'ucs2' - Alias of 'utf16le'.
'base64' - Base64 string 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].
'binary' - A way of encoding the buffer into a one-byte (latin-1)\nencoded string. The string 'latin-1' is not supported. Instead, pass\n'binary' to use 'latin-1' encoding.
'hex' - Encode each byte as two hexadecimal characters.
Buffers are also Uint8Array TypedArray instances. However, there are subtle\nincompatibilities with the TypedArray specification in ECMAScript 2015. For\ninstance, while ArrayBuffer#slice() creates a copy of the slice,\nthe implementation of [Buffer#slice()][buf.slice()] creates a view over the\nexisting Buffer without copying, making Buffer#slice() far more efficient.
It is also possible to create new TypedArray instances from a Buffer with the\nfollowing caveats:
The Buffer object's memory is copied to the TypedArray, not shared.
The Buffer object's memory is interpreted as an array of distinct\nelements, and not as a byte array of the target type. That is,\nnew Uint32Array(Buffer.from([1,2,3,4])) creates a 4-element Uint32Array\nwith elements [1,2,3,4], not a Uint32Array with a single element\n[0x1020304] or [0x4030201].
It is possible to create a new Buffer that shares the same allocated memory as\na TypedArray instance by using the TypeArray object's .buffer property:
const arr = new Uint16Array(2);\narr[0] = 5000;\narr[1] = 4000;\n\nconst buf1 = Buffer.from(arr); // copies the buffer\nconst buf2 = Buffer.from(arr.buffer); // shares the memory with arr;\n\nconsole.log(buf1);\n // Prints: <Buffer 88 a0>, copied buffer has only two elements\nconsole.log(buf2);\n // Prints: <Buffer 88 13 a0 0f>\n\narr[1] = 6000;\nconsole.log(buf1);\n // Prints: <Buffer 88 a0>\nconsole.log(buf2);\n // Prints: <Buffer 88 13 70 17>\nNote that when creating a Buffer using the TypedArray's .buffer, it is\npossible to use only a portion of the underlying ArrayBuffer by passing in\nbyteOffset and length parameters:
const arr = new Uint16Array(20);\nconst buf = Buffer.from(arr.buffer, 0, 16);\nconsole.log(buf.length);\n // Prints: 16\nThe Buffer.from() and [TypedArray.from()][] (e.g.Uint8Array.from()) have\ndifferent signatures and implementations. Specifically, the TypedArray variants\naccept a second argument that is a mapping function that is invoked on every\nelement of the typed 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_array]Buffer.from(buffer)][buffer_from_buffer]Buffer.from(arrayBuffer[, byteOffset [, length]])][buffer_from_arraybuf]Buffer.from(str[, encoding])][buffer_from_string]Buffers can be iterated over using the ECMAScript 2015 (ES6) for..of syntax:
const buf = Buffer.from([1, 2, 3]);\n\nfor (var b of buf)\n console.log(b)\n\n// Prints:\n// 1\n// 2\n// 3\nAdditionally, the [buf.values()][], [buf.keys()][], and\n[buf.entries()][] methods can be used to create iterators.
The Buffer class is a global type for dealing with binary data directly.\nIt can be constructed in a variety of ways.
\n", "classMethods": [ { "textRaw": "Class Method: Buffer.alloc(size[, fill[, encoding]])", "type": "classMethod", "name": "alloc", "meta": { "added": [ "v5.10.0" ] }, "signatures": [ { "params": [ { "textRaw": "`size` {Number} ", "name": "size", "type": "Number" }, { "textRaw": "`fill` {Value} Default: `undefined` ", "name": "fill", "type": "Value", "desc": "Default: `undefined`", "optional": true }, { "textRaw": "`encoding` {String} Default: `utf8` ", "name": "encoding", "type": "String", "desc": "Default: `utf8`", "optional": true } ] }, { "params": [ { "name": "size" }, { "name": "fill", "optional": true }, { "name": "encoding", "optional": true } ] } ], "desc": "Allocates a new Buffer of size bytes. If fill is undefined, the\nBuffer will be zero-filled.
const buf = Buffer.alloc(5);\nconsole.log(buf);\n // <Buffer 00 00 00 00 00>\nThe size must be less than or equal to the value of\nrequire('buffer').kMaxLength (on 64-bit architectures, kMaxLength is\n(2^31)-1). Otherwise, a [RangeError][] is thrown. A zero-length Buffer will\nbe created if a size less than or equal to 0 is specified.
If fill is specified, the allocated Buffer will be initialized by calling\nbuf.fill(fill). See [buf.fill()][] for more information.
const buf = Buffer.alloc(5, 'a');\nconsole.log(buf);\n // <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). For example:
const buf = Buffer.alloc(11, 'aGVsbG8gd29ybGQ=', 'base64');\nconsole.log(buf);\n // <Buffer 68 65 6c 6c 6f 20 77 6f 72 6c 64>\nCalling Buffer.alloc(size) can be significantly slower than the alternative\nBuffer.allocUnsafe(size) but ensures that the newly created Buffer instance\ncontents will never contain sensitive data.
A TypeError will be thrown if size is not a number.
Allocates a new non-zero-filled Buffer of size bytes. The size must\nbe less than or equal to the value of require('buffer').kMaxLength (on 64-bit\narchitectures, kMaxLength is (2^31)-1). Otherwise, a [RangeError][] is\nthrown. A zero-length Buffer will be created if a size less than or equal to\n0 is specified.
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 such\nBuffer instances to zeroes.
const buf = Buffer.allocUnsafe(5);\nconsole.log(buf);\n // <Buffer 78 e0 82 02 01>\n // (octets will be different, every time)\nbuf.fill(0);\nconsole.log(buf);\n // <Buffer 00 00 00 00 00>\nA TypeError will be thrown if size is not a number.
Note that 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(size) (and the deprecated\nnew Buffer(size) constructor) only when size is less than or equal to\nBuffer.poolSize >> 1 (floor of Buffer.poolSize divided by two). The default\nvalue of Buffer.poolSize is 8192 but can be modified.
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(size) provides.
Allocates a new non-zero-filled and non-pooled Buffer of size bytes. The\nsize must be less than or equal to the value of\nrequire('buffer').kMaxLength (on 64-bit architectures, kMaxLength is\n(2^31)-1). Otherwise, a [RangeError][] is thrown. A zero-length Buffer will\nbe created if a size less than or equal to 0 is specified.
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 such\nBuffer instances to zeroes.
When using Buffer.allocUnsafe() to allocate new Buffer instances,\nallocations under 4KB are, by default, sliced from a single pre-allocated\nBuffer. This allows applications to avoid the garbage collection overhead of\ncreating many individually allocated Buffers. This approach improves both\nperformance and memory usage by eliminating the need to track and cleanup as\nmany Persistent 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() then\ncopy out the relevant bits.
// need to keep around a few small chunks of memory\nconst store = [];\n\nsocket.on('readable', () => {\n const data = socket.read();\n // allocate for retained data\n const sb = Buffer.allocUnsafeSlow(10);\n // copy the data into the new allocation\n data.copy(sb, 0, 0, 10);\n store.push(sb);\n});\nUse of Buffer.allocUnsafeSlow() should be used only as a last resort after\na developer has observed undue memory retention in their applications.
A TypeError will be thrown if size is not a number.
Returns the actual byte length of a string. This is not the same as\n[String.prototype.length][] since that returns the number of characters in\na string.
Example:
\nconst str = '\\u00bd + \\u00bc = \\u00be';\n\nconsole.log(`${str}: ${str.length} characters, ` +\n `${Buffer.byteLength(str, 'utf8')} bytes`);\n\n// ½ + ¼ = ¾: 9 characters, 12 bytes\nWhen string is a Buffer/[DataView][]/[TypedArray][]/ArrayBuffer,\nreturns the actual byte length.
Otherwise, converts to String and returns the byte length of string.
Compares buf1 to buf2 typically for the purpose of sorting arrays of\nBuffers. This is equivalent is calling [buf1.compare(buf2)][].
const arr = [Buffer.from('1234'), Buffer.from('0123')];\narr.sort(Buffer.compare);\nReturns a new Buffer which is the result of concatenating all the Buffers in\nthe 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 Buffers in the\nlist. This, however, adds an additional loop to the function, so it is faster\nto provide the length explicitly.
Example: build a single Buffer from a list of three Buffers:
\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);\nconst bufA = Buffer.concat([buf1, buf2, buf3], totalLength);\nconsole.log(bufA);\nconsole.log(bufA.length);\n\n// 42\n// <Buffer 00 00 00 00 ...>\n// 42\nAllocates a new Buffer using an array of octets.
const buf = Buffer.from([0x62,0x75,0x66,0x66,0x65,0x72]);\n // creates a new Buffer containing ASCII bytes\n // ['b','u','f','f','e','r']\nA TypeError will be thrown if array is not an Array.
When passed a reference to the .buffer property of a TypedArray instance,\nthe newly created Buffer will share the same allocated memory as the\nTypedArray.
const arr = new Uint16Array(2);\narr[0] = 5000;\narr[1] = 4000;\n\nconst buf = Buffer.from(arr.buffer); // shares the memory with arr;\n\nconsole.log(buf);\n // Prints: <Buffer 88 13 a0 0f>\n\n// changing the TypedArray 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.
const ab = new ArrayBuffer(10);\nconst buf = Buffer.from(ab, 0, 2);\nconsole.log(buf.length);\n // Prints: 2\nA TypeError will be thrown if arrayBuffer is not an ArrayBuffer.
Copies the passed buffer data onto a new Buffer instance.
const buf1 = Buffer.from('buffer');\nconst buf2 = Buffer.from(buf1);\n\nbuf1[0] = 0x61;\nconsole.log(buf1.toString());\n // 'auffer'\nconsole.log(buf2.toString());\n // 'buffer' (copy is not changed)\nA TypeError will be thrown if buffer is not a Buffer.
Creates a new Buffer containing the given JavaScript string str. If\nprovided, the encoding parameter identifies the character encoding.\nIf not provided, encoding defaults to 'utf8'.
const buf1 = Buffer.from('this is a tést');\nconsole.log(buf1.toString());\n // prints: this is a tést\nconsole.log(buf1.toString('ascii'));\n // prints: this is a tC)st\n\nconst buf2 = Buffer.from('7468697320697320612074c3a97374', 'hex');\nconsole.log(buf2.toString());\n // prints: this is a tést\nA TypeError will be thrown if str is not a string.
Returns 'true' if obj is a Buffer.
Returns true if the encoding is a valid encoding argument, or false\notherwise.
The index operator [index] can be used to get and set the octet at position\nindex in the Buffer. The values refer to individual bytes, so the legal value\nrange is between 0x00 and 0xFF (hex) or 0 and 255 (decimal).
Example: copy an ASCII string into a Buffer, one byte at a time:
\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('ascii'));\n // Prints: Node.js\nReturns the amount of memory allocated for the Buffer in number of bytes. Note\nthat this does not necessarily reflect the amount of usable data within the\nBuffer. For instance, in the example below, a Buffer with 1234 bytes is\nallocated, but only 11 ASCII bytes are written.
\nconst buf = Buffer.alloc(1234);\n\nconsole.log(buf.length);\n // Prints: 1234\n\nbuf.write('some string', 0, 'ascii');\nconsole.log(buf.length);\n // Prints: 1234\nWhile the length property is not immutable, changing the value of length\ncan result in undefined and inconsistent behavior. Applications that wish to\nmodify the length of a Buffer should therefore treat length as read-only and\nuse [buf.slice()][] to create a new Buffer.
var buf = Buffer.allocUnsafe(10);\nbuf.write('abcdefghj', 0, 'ascii');\nconsole.log(buf.length);\n // Prints: 10\nbuf = buf.slice(0,5);\nconsole.log(buf.length);\n // Prints: 5\nCompares two Buffer instances and returns a number indicating whether buf\ncomes before, after, or is the same as the 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.const 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\n\n[buf1, buf2, buf3].sort(Buffer.compare);\n // produces sort order [buf1, buf3, buf2]\nThe optional targetStart, targetEnd, sourceStart, and sourceEnd\narguments can be used to limit the comparison to specific ranges within the two\nBuffer objects.
const 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\nA RangeError will be thrown if: targetStart < 0, sourceStart < 0,\ntargetEnd > target.byteLength or sourceEnd > source.byteLength.
Copies data from a region of this Buffer to a region in the target Buffer even\nif the target memory region overlaps with the source.
\nExample: build two Buffers, then copy buf1 from byte 16 through byte 19\ninto buf2, starting at the 8th byte in buf2.
const buf1 = Buffer.allocUnsafe(26);\nconst buf2 = Buffer.allocUnsafe(26).fill('!');\n\nfor (let i = 0 ; i < 26 ; i++) {\n buf1[i] = i + 97; // 97 is ASCII a\n}\n\nbuf1.copy(buf2, 8, 16, 20);\nconsole.log(buf2.toString('ascii', 0, 25));\n // Prints: !!!!!!!!qrst!!!!!!!!!!!!!\nExample: Build a single Buffer, then copy data from one region to an overlapping\nregion in the same Buffer
\nconst buf = Buffer.allocUnsafe(26);\n\nfor (var i = 0 ; i < 26 ; i++) {\n buf[i] = i + 97; // 97 is ASCII a\n}\n\nbuf.copy(buf, 0, 4, 10);\nconsole.log(buf.toString());\n\n// efghijghijklmnopqrstuvwxyz\nCreates and returns an [iterator][] of [index, byte] pairs from the Buffer\ncontents.
const buf = Buffer.from('buffer');\nfor (var 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 a boolean indicating whether this and otherBuffer have exactly the\nsame bytes.
const 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 the Buffer with the specified value. If the offset (defaults to 0)\nand end (defaults to buf.length) are not given the entire buffer will be\nfilled. The method returns a reference to the Buffer, so calls can be chained.\nThis is meant as a small simplification to creating a Buffer. Allowing the\ncreation and fill of the Buffer to be done on a single line:
const b = Buffer.allocUnsafe(50).fill('h');\nconsole.log(b.toString());\n // Prints: hhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh\nencoding is only relevant if value is a string. Otherwise it is ignored.\nvalue is coerced to a uint32 value if it is not a String or Number.
The fill() operation writes bytes into the Buffer dumbly. If the final write\nfalls in between a multi-byte character then whatever bytes fit into the buffer\nare written.
Buffer(3).fill('\\u0222');\n // Prints: <Buffer c8 a2 c8>\nOperates similar to [Array#indexOf()][] in that it returns either the\nstarting index position of value in Buffer or -1 if the Buffer does not\ncontain value. The value can be a String, Buffer or Number. Strings are by\ndefault interpreted as UTF8. Buffers will use the entire Buffer (to compare a\npartial Buffer use [buf.slice()][]). Numbers can range from 0 to 255.
const buf = Buffer.from('this is a buffer');\n\nbuf.indexOf('this');\n // returns 0\nbuf.indexOf('is');\n // returns 2\nbuf.indexOf(Buffer.from('a buffer'));\n // returns 8\nbuf.indexOf(97); // ascii for 'a'\n // returns 8\nbuf.indexOf(Buffer.from('a buffer example'));\n // returns -1\nbuf.indexOf(Buffer.from('a buffer example').slice(0,8));\n // returns 8\n\nconst utf16Buffer = Buffer.from('\\u039a\\u0391\\u03a3\\u03a3\\u0395', 'ucs2');\n\nutf16Buffer.indexOf('\\u03a3', 0, 'ucs2');\n // returns 4\nutf16Buffer.indexOf('\\u03a3', -4, 'ucs2');\n // returns 6\nOperates similar to [Array#includes()][]. The value can be a String, Buffer\nor Number. Strings are interpreted as UTF8 unless overridden with the\nencoding argument. Buffers will use the entire Buffer (to compare a partial\nBuffer use [buf.slice()][]). Numbers can range from 0 to 255.
The byteOffset indicates the index in buf where searching begins.
const buf = Buffer.from('this is a buffer');\n\nbuf.includes('this');\n // returns true\nbuf.includes('is');\n // returns true\nbuf.includes(Buffer.from('a buffer'));\n // returns true\nbuf.includes(97); // ascii for 'a'\n // returns true\nbuf.includes(Buffer.from('a buffer example'));\n // returns false\nbuf.includes(Buffer.from('a buffer example').slice(0,8));\n // returns true\nbuf.includes('this', 4);\n // returns false\nCreates and returns an [iterator][] of Buffer keys (indices).
\nconst buf = Buffer.from('buffer');\nfor (var 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 [Buffer#indexOf()][], but searches the Buffer from back to front\ninstead of front to back. Returns the starting index position of value in\nBuffer or -1 if the Buffer does not contain value. The value can be a\nString, Buffer or Number. Strings are by default interpreted as UTF8. If\nbyteOffset is provided, will return the last match that begins at or before\nbyteOffset.
const buf = new Buffer('this buffer is a buffer');\n\nbuf.lastIndexOf('this');\n // returns 0\nbuf.lastIndexOf('buffer');\n // returns 17\nbuf.lastIndexOf(new Buffer('buffer'));\n // returns 17\nbuf.lastIndexOf(97); // ascii for 'a'\n // returns 15\nbuf.lastIndexOf(new Buffer('yolo'));\n // returns -1\nbuf.lastIndexOf('buffer', 5)\n // returns 5\nbuf.lastIndexOf('buffer', 4)\n // returns -1\n\nconst utf16Buffer = new Buffer('\\u039a\\u0391\\u03a3\\u03a3\\u0395', 'ucs2');\n\nutf16Buffer.lastIndexOf('\\u03a3', null, 'ucs2');\n // returns 6\nutf16Buffer.lastIndexOf('\\u03a3', -5, 'ucs2');\n // returns 4\nReads a 64-bit double from the Buffer at the specified offset with specified\nendian format (readDoubleBE() returns big endian, readDoubleLE() returns\nlittle endian).
Setting noAssert to true skips validation of the offset. This allows the\noffset to be beyond the end of the Buffer.
const buf = Buffer.from([1,2,3,4,5,6,7,8]);\n\nbuf.readDoubleBE();\n // Returns: 8.20788039913184e-304\nbuf.readDoubleLE();\n // Returns: 5.447603722011605e-270\nbuf.readDoubleLE(1);\n // throws RangeError: Index out of range\n\nbuf.readDoubleLE(1, true); // Warning: reads passed end of buffer!\n // Segmentation fault! don't do this!\nReads a 64-bit double from the Buffer at the specified offset with specified\nendian format (readDoubleBE() returns big endian, readDoubleLE() returns\nlittle endian).
Setting noAssert to true skips validation of the offset. This allows the\noffset to be beyond the end of the Buffer.
const buf = Buffer.from([1,2,3,4,5,6,7,8]);\n\nbuf.readDoubleBE();\n // Returns: 8.20788039913184e-304\nbuf.readDoubleLE();\n // Returns: 5.447603722011605e-270\nbuf.readDoubleLE(1);\n // throws RangeError: Index out of range\n\nbuf.readDoubleLE(1, true); // Warning: reads passed end of buffer!\n // Segmentation fault! don't do this!\nReads a 32-bit float from the Buffer at the specified offset with specified\nendian format (readFloatBE() returns big endian, readFloatLE() returns\nlittle endian).
Setting noAssert to true skips validation of the offset. This allows the\noffset to be beyond the end of the Buffer.
const buf = Buffer.from([1,2,3,4]);\n\nbuf.readFloatBE();\n // Returns: 2.387939260590663e-38\nbuf.readFloatLE();\n // Returns: 1.539989614439558e-36\nbuf.readFloatLE(1);\n // throws RangeError: Index out of range\n\nbuf.readFloatLE(1, true); // Warning: reads passed end of buffer!\n // Segmentation fault! don't do this!\nReads a 32-bit float from the Buffer at the specified offset with specified\nendian format (readFloatBE() returns big endian, readFloatLE() returns\nlittle endian).
Setting noAssert to true skips validation of the offset. This allows the\noffset to be beyond the end of the Buffer.
const buf = Buffer.from([1,2,3,4]);\n\nbuf.readFloatBE();\n // Returns: 2.387939260590663e-38\nbuf.readFloatLE();\n // Returns: 1.539989614439558e-36\nbuf.readFloatLE(1);\n // throws RangeError: Index out of range\n\nbuf.readFloatLE(1, true); // Warning: reads passed end of buffer!\n // Segmentation fault! don't do this!\nReads a signed 8-bit integer from the Buffer at the specified offset.
Setting noAssert to true skips validation of the offset. This allows the\noffset to be beyond the end of the Buffer.
Integers read from the Buffer are interpreted as two's complement signed values.
\nconst buf = Buffer.from([1,-2,3,4]);\n\nbuf.readInt8(0);\n // returns 1\nbuf.readInt8(1);\n // returns -2\nReads a signed 16-bit integer from the Buffer at the specified offset with\nthe specified endian format (readInt16BE() returns big endian,\nreadInt16LE() returns little endian).
Setting noAssert to true skips validation of the offset. This allows the\noffset to be beyond the end of the Buffer.
Integers read from the Buffer are interpreted as two's complement signed values.
\nconst buf = Buffer.from([1,-2,3,4]);\n\nbuf.readInt16BE();\n // returns 510\nbuf.readInt16LE(1);\n // returns 1022\nReads a signed 16-bit integer from the Buffer at the specified offset with\nthe specified endian format (readInt16BE() returns big endian,\nreadInt16LE() returns little endian).
Setting noAssert to true skips validation of the offset. This allows the\noffset to be beyond the end of the Buffer.
Integers read from the Buffer are interpreted as two's complement signed values.
\nconst buf = Buffer.from([1,-2,3,4]);\n\nbuf.readInt16BE();\n // returns 510\nbuf.readInt16LE(1);\n // returns 1022\nReads a signed 32-bit integer from the Buffer at the specified offset with\nthe specified endian format (readInt32BE() returns big endian,\nreadInt32LE() returns little endian).
Setting noAssert to true skips validation of the offset. This allows the\noffset to be beyond the end of the Buffer.
Integers read from the Buffer are interpreted as two's complement signed values.
\nconst buf = Buffer.from([1,-2,3,4]);\n\nbuf.readInt32BE();\n // returns 33424132\nbuf.readInt32LE();\n // returns 67370497\nbuf.readInt32LE(1);\n // throws RangeError: Index out of range\nReads a signed 32-bit integer from the Buffer at the specified offset with\nthe specified endian format (readInt32BE() returns big endian,\nreadInt32LE() returns little endian).
Setting noAssert to true skips validation of the offset. This allows the\noffset to be beyond the end of the Buffer.
Integers read from the Buffer are interpreted as two's complement signed values.
\nconst buf = Buffer.from([1,-2,3,4]);\n\nbuf.readInt32BE();\n // returns 33424132\nbuf.readInt32LE();\n // returns 67370497\nbuf.readInt32LE(1);\n // throws RangeError: Index out of range\nReads byteLength number of bytes from the Buffer at the specified offset\nand interprets the result as a two's complement signed value. Supports up to 48\nbits of accuracy. For example:
const buf = Buffer.allocUnsafe(6);\nbuf.writeUInt16LE(0x90ab, 0);\nbuf.writeUInt32LE(0x12345678, 2);\nbuf.readIntLE(0, 6).toString(16); // Specify 6 bytes (48 bits)\n// Returns: '1234567890ab'\n\nbuf.readIntBE(0, 6).toString(16);\n// Returns: -546f87a9cbee\nSetting noAssert to true skips validation of the offset. This allows the\noffset to be beyond the end of the Buffer.
Reads byteLength number of bytes from the Buffer at the specified offset\nand interprets the result as a two's complement signed value. Supports up to 48\nbits of accuracy. For example:
const buf = Buffer.allocUnsafe(6);\nbuf.writeUInt16LE(0x90ab, 0);\nbuf.writeUInt32LE(0x12345678, 2);\nbuf.readIntLE(0, 6).toString(16); // Specify 6 bytes (48 bits)\n// Returns: '1234567890ab'\n\nbuf.readIntBE(0, 6).toString(16);\n// Returns: -546f87a9cbee\nSetting noAssert to true skips validation of the offset. This allows the\noffset to be beyond the end of the Buffer.
Reads an unsigned 8-bit integer from the Buffer at the specified offset.
Setting noAssert to true skips validation of the offset. This allows the\noffset to be beyond the end of the Buffer.
const buf = Buffer.from([1,-2,3,4]);\n\nbuf.readUInt8(0);\n // returns 1\nbuf.readUInt8(1);\n // returns 254\nReads an unsigned 16-bit integer from the Buffer at the specified offset with\nspecified endian format (readUInt16BE() returns big endian,\nreadUInt16LE() returns little endian).
Setting noAssert to true skips validation of the offset. This allows the\noffset to be beyond the end of the Buffer.
Example:
\nconst buf = Buffer.from([0x3, 0x4, 0x23, 0x42]);\n\nbuf.readUInt16BE(0);\n // Returns: 0x0304\nbuf.readUInt16LE(0);\n // Returns: 0x0403\nbuf.readUInt16BE(1);\n // Returns: 0x0423\nbuf.readUInt16LE(1);\n // Returns: 0x2304\nbuf.readUInt16BE(2);\n // Returns: 0x2342\nbuf.readUInt16LE(2);\n // Returns: 0x4223\nReads an unsigned 16-bit integer from the Buffer at the specified offset with\nspecified endian format (readUInt16BE() returns big endian,\nreadUInt16LE() returns little endian).
Setting noAssert to true skips validation of the offset. This allows the\noffset to be beyond the end of the Buffer.
Example:
\nconst buf = Buffer.from([0x3, 0x4, 0x23, 0x42]);\n\nbuf.readUInt16BE(0);\n // Returns: 0x0304\nbuf.readUInt16LE(0);\n // Returns: 0x0403\nbuf.readUInt16BE(1);\n // Returns: 0x0423\nbuf.readUInt16LE(1);\n // Returns: 0x2304\nbuf.readUInt16BE(2);\n // Returns: 0x2342\nbuf.readUInt16LE(2);\n // Returns: 0x4223\nReads an unsigned 32-bit integer from the Buffer at the specified offset with\nspecified endian format (readUInt32BE() returns big endian,\nreadUInt32LE() returns little endian).
Setting noAssert to true skips validation of the offset. This allows the\noffset to be beyond the end of the Buffer.
Example:
\nconst buf = Buffer.from([0x3, 0x4, 0x23, 0x42]);\n\nbuf.readUInt32BE(0);\n // Returns: 0x03042342\nconsole.log(buf.readUInt32LE(0));\n // Returns: 0x42230403\nReads an unsigned 32-bit integer from the Buffer at the specified offset with\nspecified endian format (readUInt32BE() returns big endian,\nreadUInt32LE() returns little endian).
Setting noAssert to true skips validation of the offset. This allows the\noffset to be beyond the end of the Buffer.
Example:
\nconst buf = Buffer.from([0x3, 0x4, 0x23, 0x42]);\n\nbuf.readUInt32BE(0);\n // Returns: 0x03042342\nconsole.log(buf.readUInt32LE(0));\n // Returns: 0x42230403\nReads byteLength number of bytes from the Buffer at the specified offset\nand interprets the result as an unsigned integer. Supports up to 48\nbits of accuracy. For example:
const buf = Buffer.allocUnsafe(6);\nbuf.writeUInt16LE(0x90ab, 0);\nbuf.writeUInt32LE(0x12345678, 2);\nbuf.readUIntLE(0, 6).toString(16); // Specify 6 bytes (48 bits)\n// Returns: '1234567890ab'\n\nbuf.readUIntBE(0, 6).toString(16);\n// Returns: ab9078563412\nSetting noAssert to true skips validation of the offset. This allows the\noffset to be beyond the end of the Buffer.
Reads byteLength number of bytes from the Buffer at the specified offset\nand interprets the result as an unsigned integer. Supports up to 48\nbits of accuracy. For example:
const buf = Buffer.allocUnsafe(6);\nbuf.writeUInt16LE(0x90ab, 0);\nbuf.writeUInt32LE(0x12345678, 2);\nbuf.readUIntLE(0, 6).toString(16); // Specify 6 bytes (48 bits)\n// Returns: '1234567890ab'\n\nbuf.readUIntBE(0, 6).toString(16);\n// Returns: ab9078563412\nSetting noAssert to true skips validation of the offset. This allows the\noffset to be beyond the end of the Buffer.
Returns a new Buffer that references the same memory as the original, but\noffset and cropped by the start and end indices.
Note that modifying the new Buffer slice will modify the memory in the\noriginal Buffer because the allocated memory of the two objects overlap.
\nExample: build a Buffer with the ASCII alphabet, take a slice, then modify one\nbyte from the original Buffer.
\nconst buf1 = Buffer.allocUnsafe(26);\n\nfor (var i = 0 ; i < 26 ; i++) {\n buf1[i] = i + 97; // 97 is ASCII a\n}\n\nconst buf2 = buf1.slice(0, 3);\nbuf2.toString('ascii', 0, buf2.length);\n // Returns: 'abc'\nbuf1[0] = 33;\nbuf2.toString('ascii', 0, buf2.length);\n // Returns : '!bc'\nSpecifying negative indexes causes the slice to be generated relative to the\nend of the Buffer rather than the beginning.
\nconst buf = Buffer.from('buffer');\n\nbuf.slice(-6, -1).toString();\n // Returns 'buffe', equivalent to buf.slice(0, 5)\nbuf.slice(-6, -2).toString();\n // Returns 'buff', equivalent to buf.slice(0, 4)\nbuf.slice(-5, -2).toString();\n // Returns 'uff', equivalent to buf.slice(1, 4)\nInterprets the Buffer as an array of unsigned 16-bit integers and swaps\nthe byte-order in-place. Throws a RangeError if the Buffer length is\nnot a multiple of 16 bits. The method returns a reference to the Buffer, so\ncalls can be chained.
const buf = Buffer.from([0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8]);\nconsole.log(buf);\n // Prints Buffer(0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8)\nbuf.swap16();\nconsole.log(buf);\n // Prints Buffer(0x2, 0x1, 0x4, 0x3, 0x6, 0x5, 0x8, 0x7)\nInterprets the Buffer as an array of unsigned 32-bit integers and swaps\nthe byte-order in-place. Throws a RangeError if the Buffer length is\nnot a multiple of 32 bits. The method returns a reference to the Buffer, so\ncalls can be chained.
const buf = Buffer.from([0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8]);\nconsole.log(buf);\n // Prints Buffer(0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8)\nbuf.swap32();\nconsole.log(buf);\n // Prints Buffer(0x4, 0x3, 0x2, 0x1, 0x8, 0x7, 0x6, 0x5)\nDecodes and returns a string from the Buffer data using the specified\ncharacter set encoding.
const buf = Buffer.allocUnsafe(26);\nfor (var i = 0 ; i < 26 ; i++) {\n buf[i] = i + 97; // 97 is ASCII a\n}\nbuf.toString('ascii');\n // Returns: 'abcdefghijklmnopqrstuvwxyz'\nbuf.toString('ascii',0,5);\n // Returns: 'abcde'\nbuf.toString('utf8',0,5);\n // Returns: 'abcde'\nbuf.toString(undefined,0,5);\n // Returns: 'abcde', encoding defaults to 'utf8'\nReturns a JSON representation of the Buffer instance. [JSON.stringify()][]\nimplicitly calls this function when stringifying a Buffer instance.
Example:
\nconst buf = Buffer.from('test');\nconst json = JSON.stringify(buf);\n\nconsole.log(json);\n// Prints: '{"type":"Buffer","data":[116,101,115,116]}'\n\nconst copy = JSON.parse(json, (key, value) => {\n return value && value.type === 'Buffer'\n ? Buffer.from(value.data)\n : value;\n });\n\nconsole.log(copy.toString());\n// Prints: 'test'\nCreates and returns an [iterator][] for Buffer values (bytes). This function is\ncalled automatically when the Buffer is used in a for..of statement.
const buf = Buffer.from('buffer');\nfor (var 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 (var 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 the Buffer at offset using the given encoding.\nThe length parameter is the number of bytes to write. If the Buffer did not\ncontain enough space to fit the entire string, only a partial amount of the\nstring will be written however, it will not write only partially encoded\ncharacters.
const buf = Buffer.allocUnsafe(256);\nconst len = buf.write('\\u00bd + \\u00bc = \\u00be', 0);\nconsole.log(`${len} bytes: ${buf.toString('utf8', 0, len)}`);\n // Prints: 12 bytes: ½ + ¼ = ¾\nWrites value to the Buffer at the specified offset with specified endian\nformat (writeDoubleBE() writes big endian, writeDoubleLE() writes little\nendian). The value argument should be a valid 64-bit double. Behavior is\nnot defined when value is anything other than a 64-bit double.
Set noAssert to true to skip validation of value and offset. This means\nthat value may be too large for the specific function and offset may be\nbeyond the end of the Buffer leading to the values being silently dropped. This\nshould not be used unless you are certain of correctness.
Example:
\nconst buf = Buffer.allocUnsafe(8);\nbuf.writeDoubleBE(0xdeadbeefcafebabe, 0);\n\nconsole.log(buf);\n // Prints: <Buffer 43 eb d5 b7 dd f9 5f d7>\n\nbuf.writeDoubleLE(0xdeadbeefcafebabe, 0);\n\nconsole.log(buf);\n // Prints: <Buffer d7 5f f9 dd b7 d5 eb 43>\nWrites value to the Buffer at the specified offset with specified endian\nformat (writeDoubleBE() writes big endian, writeDoubleLE() writes little\nendian). The value argument should be a valid 64-bit double. Behavior is\nnot defined when value is anything other than a 64-bit double.
Set noAssert to true to skip validation of value and offset. This means\nthat value may be too large for the specific function and offset may be\nbeyond the end of the Buffer leading to the values being silently dropped. This\nshould not be used unless you are certain of correctness.
Example:
\nconst buf = Buffer.allocUnsafe(8);\nbuf.writeDoubleBE(0xdeadbeefcafebabe, 0);\n\nconsole.log(buf);\n // Prints: <Buffer 43 eb d5 b7 dd f9 5f d7>\n\nbuf.writeDoubleLE(0xdeadbeefcafebabe, 0);\n\nconsole.log(buf);\n // Prints: <Buffer d7 5f f9 dd b7 d5 eb 43>\nWrites value to the Buffer at the specified offset with specified endian\nformat (writeFloatBE() writes big endian, writeFloatLE() writes little\nendian). Behavior is not defined when value is anything other than a 32-bit\nfloat.
Set noAssert to true to skip validation of value and offset. This means\nthat value may be too large for the specific function and offset may be\nbeyond the end of the Buffer leading to the values being silently dropped. This\nshould not be used unless you are certain of correctness.
Example:
\nconst buf = Buffer.allocUnsafe(4);\nbuf.writeFloatBE(0xcafebabe, 0);\n\nconsole.log(buf);\n // Prints: <Buffer 4f 4a fe bb>\n\nbuf.writeFloatLE(0xcafebabe, 0);\n\nconsole.log(buf);\n // Prints: <Buffer bb fe 4a 4f>\nWrites value to the Buffer at the specified offset with specified endian\nformat (writeFloatBE() writes big endian, writeFloatLE() writes little\nendian). Behavior is not defined when value is anything other than a 32-bit\nfloat.
Set noAssert to true to skip validation of value and offset. This means\nthat value may be too large for the specific function and offset may be\nbeyond the end of the Buffer leading to the values being silently dropped. This\nshould not be used unless you are certain of correctness.
Example:
\nconst buf = Buffer.allocUnsafe(4);\nbuf.writeFloatBE(0xcafebabe, 0);\n\nconsole.log(buf);\n // Prints: <Buffer 4f 4a fe bb>\n\nbuf.writeFloatLE(0xcafebabe, 0);\n\nconsole.log(buf);\n // Prints: <Buffer bb fe 4a 4f>\nWrites value to the Buffer at the specified offset. The value should be a\nvalid signed 8-bit integer. Behavior is not defined when value is anything\nother than a signed 8-bit integer.
Set noAssert to true to skip validation of value and offset. This means\nthat value may be too large for the specific function and offset may be\nbeyond the end of the Buffer leading to the values being silently dropped. This\nshould not be used unless you are certain of correctness.
The value is interpreted and written as a two's complement signed integer.
const buf = Buffer.allocUnsafe(2);\nbuf.writeInt8(2, 0);\nbuf.writeInt8(-2, 1);\nconsole.log(buf);\n // Prints: <Buffer 02 fe>\nWrites value to the Buffer at the specified offset with specified endian\nformat (writeInt16BE() writes big endian, writeInt16LE() writes little\nendian). The value should be a valid signed 16-bit integer. Behavior is\nnot defined when value is anything other than a signed 16-bit integer.
Set noAssert to true to skip validation of value and offset. This means\nthat value may be too large for the specific function and offset may be\nbeyond the end of the Buffer leading to the values being silently dropped. This\nshould not be used unless you are certain of correctness.
The value is interpreted and written as a two's complement signed integer.
const buf = Buffer.allocUnsafe(4);\nbuf.writeInt16BE(0x0102,0);\nbuf.writeInt16LE(0x0304,2);\nconsole.log(buf);\n // Prints: <Buffer 01 02 04 03>\nWrites value to the Buffer at the specified offset with specified endian\nformat (writeInt16BE() writes big endian, writeInt16LE() writes little\nendian). The value should be a valid signed 16-bit integer. Behavior is\nnot defined when value is anything other than a signed 16-bit integer.
Set noAssert to true to skip validation of value and offset. This means\nthat value may be too large for the specific function and offset may be\nbeyond the end of the Buffer leading to the values being silently dropped. This\nshould not be used unless you are certain of correctness.
The value is interpreted and written as a two's complement signed integer.
const buf = Buffer.allocUnsafe(4);\nbuf.writeInt16BE(0x0102,0);\nbuf.writeInt16LE(0x0304,2);\nconsole.log(buf);\n // Prints: <Buffer 01 02 04 03>\nWrites value to the Buffer at the specified offset with specified endian\nformat (writeInt32BE() writes big endian, writeInt32LE() writes little\nendian). The value should be a valid signed 32-bit integer. Behavior is\nnot defined when value is anything other than a signed 32-bit integer.
Set noAssert to true to skip validation of value and offset. This means\nthat value may be too large for the specific function and offset may be\nbeyond the end of the Buffer leading to the values being silently dropped. This\nshould not be used unless you are certain of correctness.
The value is interpreted and written as a two's complement signed integer.
const buf = Buffer.allocUnsafe(8);\nbuf.writeInt32BE(0x01020304,0);\nbuf.writeInt32LE(0x05060708,4);\nconsole.log(buf);\n // Prints: <Buffer 01 02 03 04 08 07 06 05>\nWrites value to the Buffer at the specified offset with specified endian\nformat (writeInt32BE() writes big endian, writeInt32LE() writes little\nendian). The value should be a valid signed 32-bit integer. Behavior is\nnot defined when value is anything other than a signed 32-bit integer.
Set noAssert to true to skip validation of value and offset. This means\nthat value may be too large for the specific function and offset may be\nbeyond the end of the Buffer leading to the values being silently dropped. This\nshould not be used unless you are certain of correctness.
The value is interpreted and written as a two's complement signed integer.
const buf = Buffer.allocUnsafe(8);\nbuf.writeInt32BE(0x01020304,0);\nbuf.writeInt32LE(0x05060708,4);\nconsole.log(buf);\n // Prints: <Buffer 01 02 03 04 08 07 06 05>\nWrites value to the Buffer at the specified offset and byteLength.\nSupports up to 48 bits of accuracy. For example:
const buf1 = Buffer.allocUnsafe(6);\nbuf1.writeUIntBE(0x1234567890ab, 0, 6);\nconsole.log(buf1);\n // Prints: <Buffer 12 34 56 78 90 ab>\n\nconst buf2 = Buffer.allocUnsafe(6);\nbuf2.writeUIntLE(0x1234567890ab, 0, 6);\nconsole.log(buf2);\n // Prints: <Buffer ab 90 78 56 34 12>\nSet noAssert to true to skip validation of value and offset. This means\nthat value may be too large for the specific function and offset may be\nbeyond the end of the Buffer leading to the values being silently dropped. This\nshould not be used unless you are certain of correctness.
Behavior is not defined when value is anything other than an integer.
Writes value to the Buffer at the specified offset and byteLength.\nSupports up to 48 bits of accuracy. For example:
const buf1 = Buffer.allocUnsafe(6);\nbuf1.writeUIntBE(0x1234567890ab, 0, 6);\nconsole.log(buf1);\n // Prints: <Buffer 12 34 56 78 90 ab>\n\nconst buf2 = Buffer.allocUnsafe(6);\nbuf2.writeUIntLE(0x1234567890ab, 0, 6);\nconsole.log(buf2);\n // Prints: <Buffer ab 90 78 56 34 12>\nSet noAssert to true to skip validation of value and offset. This means\nthat value may be too large for the specific function and offset may be\nbeyond the end of the Buffer leading to the values being silently dropped. This\nshould not be used unless you are certain of correctness.
Behavior is not defined when value is anything other than an integer.
Writes value to the Buffer at the specified offset. The value should be a\nvalid unsigned 8-bit integer. Behavior is not defined when value is anything\nother than an unsigned 8-bit integer.
Set noAssert to true to skip validation of value and offset. This means\nthat value may be too large for the specific function and offset may be\nbeyond the end of the Buffer leading to the values being silently dropped. This\nshould not be used unless you are certain of correctness.
Example:
\nconst buf = Buffer.allocUnsafe(4);\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 the Buffer at the specified offset with specified endian\nformat (writeUInt16BE() writes big endian, writeUInt16LE() writes little\nendian). The value should be a valid unsigned 16-bit integer. Behavior is\nnot defined when value is anything other than an unsigned 16-bit integer.
Set noAssert to true to skip validation of value and offset. This means\nthat value may be too large for the specific function and offset may be\nbeyond the end of the Buffer leading to the values being silently dropped. This\nshould not be used unless you are certain of correctness.
Example:
\nconst buf = Buffer.allocUnsafe(4);\nbuf.writeUInt16BE(0xdead, 0);\nbuf.writeUInt16BE(0xbeef, 2);\n\nconsole.log(buf);\n // Prints: <Buffer de ad be ef>\n\nbuf.writeUInt16LE(0xdead, 0);\nbuf.writeUInt16LE(0xbeef, 2);\n\nconsole.log(buf);\n // Prints: <Buffer ad de ef be>\nWrites value to the Buffer at the specified offset with specified endian\nformat (writeUInt16BE() writes big endian, writeUInt16LE() writes little\nendian). The value should be a valid unsigned 16-bit integer. Behavior is\nnot defined when value is anything other than an unsigned 16-bit integer.
Set noAssert to true to skip validation of value and offset. This means\nthat value may be too large for the specific function and offset may be\nbeyond the end of the Buffer leading to the values being silently dropped. This\nshould not be used unless you are certain of correctness.
Example:
\nconst buf = Buffer.allocUnsafe(4);\nbuf.writeUInt16BE(0xdead, 0);\nbuf.writeUInt16BE(0xbeef, 2);\n\nconsole.log(buf);\n // Prints: <Buffer de ad be ef>\n\nbuf.writeUInt16LE(0xdead, 0);\nbuf.writeUInt16LE(0xbeef, 2);\n\nconsole.log(buf);\n // Prints: <Buffer ad de ef be>\nWrites value to the Buffer at the specified offset with specified endian\nformat (writeUInt32BE() writes big endian, writeUInt32LE() writes little\nendian). The value should be a valid unsigned 32-bit integer. Behavior is\nnot defined when value is anything other than an unsigned 32-bit integer.
Set noAssert to true to skip validation of value and offset. This means\nthat value may be too large for the specific function and offset may be\nbeyond the end of the Buffer leading to the values being silently dropped. This\nshould not be used unless you are certain of correctness.
Example:
\nconst buf = Buffer.allocUnsafe(4);\nbuf.writeUInt32BE(0xfeedface, 0);\n\nconsole.log(buf);\n // Prints: <Buffer fe ed fa ce>\n\nbuf.writeUInt32LE(0xfeedface, 0);\n\nconsole.log(buf);\n // Prints: <Buffer ce fa ed fe>\nWrites value to the Buffer at the specified offset with specified endian\nformat (writeUInt32BE() writes big endian, writeUInt32LE() writes little\nendian). The value should be a valid unsigned 32-bit integer. Behavior is\nnot defined when value is anything other than an unsigned 32-bit integer.
Set noAssert to true to skip validation of value and offset. This means\nthat value may be too large for the specific function and offset may be\nbeyond the end of the Buffer leading to the values being silently dropped. This\nshould not be used unless you are certain of correctness.
Example:
\nconst buf = Buffer.allocUnsafe(4);\nbuf.writeUInt32BE(0xfeedface, 0);\n\nconsole.log(buf);\n // Prints: <Buffer fe ed fa ce>\n\nbuf.writeUInt32LE(0xfeedface, 0);\n\nconsole.log(buf);\n // Prints: <Buffer ce fa ed fe>\nWrites value to the Buffer at the specified offset and byteLength.\nSupports up to 48 bits of accuracy. For example:
const buf = Buffer.allocUnsafe(6);\nbuf.writeUIntBE(0x1234567890ab, 0, 6);\nconsole.log(buf);\n // Prints: <Buffer 12 34 56 78 90 ab>\nSet noAssert to true to skip validation of value and offset. This means\nthat value may be too large for the specific function and offset may be\nbeyond the end of the Buffer leading to the values being silently dropped. This\nshould not be used unless you are certain of correctness.
Behavior is not defined when value is anything other than an unsigned integer.
Writes value to the Buffer at the specified offset and byteLength.\nSupports up to 48 bits of accuracy. For example:
const buf = Buffer.allocUnsafe(6);\nbuf.writeUIntBE(0x1234567890ab, 0, 6);\nconsole.log(buf);\n // Prints: <Buffer 12 34 56 78 90 ab>\nSet noAssert to true to skip validation of value and offset. This means\nthat value may be too large for the specific function and offset may be\nbeyond the end of the Buffer leading to the values being silently dropped. This\nshould not be used unless you are certain of correctness.
Behavior is not defined when value is anything other than an unsigned integer.
Stability: 0 - Deprecated: Use [`Buffer.from(array)`][buffer_from_array]\ninstead.\narray {Array}Allocates a new Buffer using an array of octets.
const buf = new Buffer([0x62,0x75,0x66,0x66,0x65,0x72]);\n // creates a new Buffer containing ASCII bytes\n // ['b','u','f','f','e','r']\nStability: 0 - Deprecated: Use [`Buffer.from(buffer)`][buffer_from_buffer]\ninstead.\nbuffer {Buffer}Copies the passed buffer data onto a new Buffer instance.
const buf1 = new Buffer('buffer');\nconst buf2 = new Buffer(buf1);\n\nbuf1[0] = 0x61;\nconsole.log(buf1.toString());\n // 'auffer'\nconsole.log(buf2.toString());\n // 'buffer' (copy is not changed)\nStability: 0 - Deprecated: Use\n[`Buffer.from(arrayBuffer[, byteOffset [, length]])`][buffer_from_arraybuf]\ninstead.\narrayBuffer {ArrayBuffer} The .buffer property of a TypedArray or a\nnew ArrayBuffer()byteOffset {Number} Default: 0length {Number} Default: arrayBuffer.length - byteOffsetWhen passed a reference to the .buffer property of a TypedArray instance,\nthe newly created Buffer will share the same allocated memory as the\nTypedArray.
The optional byteOffset and length arguments specify a memory range within\nthe arrayBuffer that will be shared by the Buffer.
const arr = new Uint16Array(2);\narr[0] = 5000;\narr[1] = 4000;\n\nconst buf = new Buffer(arr.buffer); // shares the memory with arr;\n\nconsole.log(buf);\n // Prints: <Buffer 88 13 a0 0f>\n\n// changing the TypdArray changes the Buffer also\narr[1] = 6000;\n\nconsole.log(buf);\n // Prints: <Buffer 88 13 70 17>\nStability: 0 - Deprecated: Use\n[`Buffer.alloc(size[, fill[, encoding]])`][buffer_alloc] instead (also\nsee [`Buffer.allocUnsafe(size)`][buffer_allocunsafe]).\nsize {Number}Allocates a new Buffer of size bytes. The size must be less than\nor equal to the value of require('buffer').kMaxLength (on 64-bit\narchitectures, kMaxLength is (2^31)-1). Otherwise, a [RangeError][] is\nthrown. A zero-length Buffer will be created if a size less than or equal to\n0 is specified.
Unlike ArrayBuffers, the underlying memory for Buffer instances created in\nthis way is not initialized. The contents of a newly created Buffer are\nunknown and could contain sensitive data. Use [buf.fill(0)][] to initialize\na Buffer to zeroes.
const buf = new Buffer(5);\nconsole.log(buf);\n // <Buffer 78 e0 82 02 01>\n // (octets will be different, every time)\nbuf.fill(0);\nconsole.log(buf);\n // <Buffer 00 00 00 00 00>\nStability: 0 - Deprecated:\nUse [`Buffer.from(str[, encoding])`][buffer_from_string] instead.\nstr {String} string to encode.encoding {String} Default: 'utf8'Creates a new Buffer containing the given JavaScript string str. If\nprovided, the encoding parameter identifies the strings character encoding.
const buf1 = new Buffer('this is a tést');\nconsole.log(buf1.toString());\n // prints: this is a tést\nconsole.log(buf1.toString('ascii'));\n // prints: this is a tC)st\n\nconst buf2 = new Buffer('7468697320697320612074c3a97374', 'hex');\nconsole.log(buf2.toString());\n // prints: this is a tést\nStability: 0 - Deprecated: Use\n[`Buffer.allocUnsafeSlow(size)`][buffer_allocunsafeslow] instead.\nReturns an un-pooled Buffer.
In order to avoid the garbage collection overhead of creating many individually\nallocated Buffers, by default allocations under 4KB are sliced from a single\nlarger allocated object. This approach improves both performance and memory\nusage since v8 does not need to track and cleanup as many Persistent objects.
In the case where a developer may need to retain a small chunk of memory from a\npool for an indeterminate amount of time, it may be appropriate to create an\nun-pooled Buffer instance using SlowBuffer then copy out the relevant bits.
// need to keep around a few small chunks of memory\nconst store = [];\n\nsocket.on('readable', () => {\n var data = socket.read();\n // allocate for retained data\n var sb = SlowBuffer(10);\n // copy the data into the new allocation\n data.copy(sb, 0, 0, 10);\n store.push(sb);\n});\nUse of SlowBuffer should be used only as a last resort after a developer\nhas observed undue memory retention in their applications.
Stability: 0 - Deprecated: Use\n[`Buffer.allocUnsafeSlow(size)`][buffer_allocunsafeslow] instead.\nsize NumberAllocates a new SlowBuffer of size bytes. The size must be less than\nor equal to the value of require('buffer').kMaxLength (on 64-bit\narchitectures, kMaxLength is (2^31)-1). Otherwise, a [RangeError][] is\nthrown. A zero-length Buffer will be created if a size less than or equal to\n0 is specified.
The underlying memory for SlowBuffer instances is not initialized. The\ncontents of a newly created SlowBuffer are unknown and could contain\nsensitive data. Use [buf.fill(0)][] to initialize a SlowBuffer to zeroes.
const SlowBuffer = require('buffer').SlowBuffer;\nconst buf = new SlowBuffer(5);\nconsole.log(buf);\n // <Buffer 78 e0 82 02 01>\n // (octets will be different, every time)\nbuf.fill(0);\nconsole.log(buf);\n // <Buffer 00 00 00 00 00>\nReturns the maximum number of bytes that will be returned when\nbuffer.inspect() is called. This can be overridden by user modules. See\n[util.inspect()][] for more details on buffer.inspect() behavior.
Note that this is a property on the buffer module as returned by\nrequire('buffer'), not on the Buffer global or a Buffer instance.