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{
"source": "doc/api/buffer.md",
"modules": [
{
"textRaw": "Buffer",
"name": "buffer",
"introduced_in": "v0.1.90",
"desc": "<!--lint disable maximum-line-length-->\n<blockquote>\n<p>Stability: 2 - Stable</p>\n</blockquote>\n<p>Prior to the introduction of <a href=\"https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray\"><code>TypedArray</code></a>, the JavaScript language had no\nmechanism for reading or manipulating streams of binary data. The <code>Buffer</code> class\nwas introduced as part of the Node.js API to make it possible to interact with\noctet streams in the context of things like TCP streams and file system\noperations.</p>\n<p>With <a href=\"https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray\"><code>TypedArray</code></a> now available, the <code>Buffer</code> class implements the\n<a href=\"https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint8Array\"><code>Uint8Array</code></a> API in a manner that is more optimized and suitable for Node.js.</p>\n<p>Instances of the <code>Buffer</code> class are similar to arrays of integers but\ncorrespond to fixed-sized, raw memory allocations outside the V8 heap.\nThe size of the <code>Buffer</code> is established when it is created and cannot be\nchanged.</p>\n<p>The <code>Buffer</code> class is within the global scope, making it unlikely that one\nwould need to ever use <code>require('buffer').Buffer</code>.</p>\n<pre><code class=\"lang-js\">// Creates a zero-filled Buffer of length 10.\nconst buf1 = Buffer.alloc(10);\n\n// Creates a Buffer of length 10, filled with 0x1.\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 either fill() or write().\nconst buf3 = Buffer.allocUnsafe(10);\n\n// Creates a Buffer containing [0x1, 0x2, 0x3].\nconst buf4 = Buffer.from([1, 2, 3]);\n\n// Creates a Buffer containing UTF-8 bytes [0x74, 0xc3, 0xa9, 0x73, 0x74].\nconst buf5 = Buffer.from('tést');\n\n// Creates a Buffer containing Latin-1 bytes [0x74, 0xe9, 0x73, 0x74].\nconst buf6 = Buffer.from('tést', 'latin1');\n</code></pre>\n",
"modules": [
{
"textRaw": "`Buffer.from()`, `Buffer.alloc()`, and `Buffer.allocUnsafe()`",
"name": "`buffer.from()`,_`buffer.alloc()`,_and_`buffer.allocunsafe()`",
"desc": "<p>In versions of Node.js prior to 6.0.0, <code>Buffer</code> instances were created using the\n<code>Buffer</code> constructor function, which allocates the returned <code>Buffer</code>\ndifferently based on what arguments are provided:</p>\n<ul>\n<li>Passing a number as the first argument to <code>Buffer()</code> (e.g. <code>new Buffer(10)</code>)\nallocates a new <code>Buffer</code> object of the specified size. Prior to Node.js 8.0.0,\nthe memory allocated for such <code>Buffer</code> instances is <em>not</em> initialized and\n<em>can contain sensitive data</em>. Such <code>Buffer</code> instances <em>must</em> be subsequently\ninitialized by using either <a href=\"#buffer_buf_fill_value_offset_end_encoding\"><code>buf.fill(0)</code></a> or by writing to the\nentire <code>Buffer</code>. While this behavior is <em>intentional</em> to improve performance,\ndevelopment experience has demonstrated that a more explicit distinction is\nrequired between creating a fast-but-uninitialized <code>Buffer</code> versus creating a\nslower-but-safer <code>Buffer</code>. Starting in Node.js 8.0.0, <code>Buffer(num)</code> and\n<code>new Buffer(num)</code> will return a <code>Buffer</code> with initialized memory.</li>\n<li>Passing a string, array, or <code>Buffer</code> as the first argument copies the\npassed object's data into the <code>Buffer</code>.</li>\n<li>Passing an <a href=\"https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer\"><code>ArrayBuffer</code></a> or a <a href=\"https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/SharedArrayBuffer\"><code>SharedArrayBuffer</code></a> returns a <code>Buffer</code> that\nshares allocated memory with the given array buffer.</li>\n</ul>\n<p>Because the behavior of <code>new Buffer()</code> is different depending on the type of the\nfirst argument, security and reliability issues can be inadvertently introduced\ninto applications when argument validation or <code>Buffer</code> initialization is not\nperformed.</p>\n<p>To make the creation of <code>Buffer</code> instances more reliable and less error-prone,\nthe various forms of the <code>new Buffer()</code> constructor have been <strong>deprecated</strong>\nand replaced by separate <code>Buffer.from()</code>, <a href=\"#buffer_class_method_buffer_alloc_size_fill_encoding\"><code>Buffer.alloc()</code></a>, and\n<a href=\"#buffer_class_method_buffer_allocunsafe_size\"><code>Buffer.allocUnsafe()</code></a> methods.</p>\n<p><em>Developers should migrate all existing uses of the <code>new Buffer()</code> constructors\nto one of these new APIs.</em></p>\n<ul>\n<li><a href=\"#buffer_class_method_buffer_from_array\"><code>Buffer.from(array)</code></a> returns a new <code>Buffer</code> that <em>contains a copy</em> of the\nprovided octets.</li>\n<li><a href=\"#buffer_class_method_buffer_from_arraybuffer_byteoffset_length\"><code>Buffer.from(arrayBuffer[, byteOffset [, length]])</code></a>\nreturns a new <code>Buffer</code> that <em>shares the same allocated memory</em> as the given\n<a href=\"https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer\"><code>ArrayBuffer</code></a>.</li>\n<li><a href=\"#buffer_class_method_buffer_from_buffer\"><code>Buffer.from(buffer)</code></a> returns a new <code>Buffer</code> that <em>contains a copy</em> of the\ncontents of the given <code>Buffer</code>.</li>\n<li><a href=\"#buffer_class_method_buffer_from_string_encoding\"><code>Buffer.from(string[, encoding])</code></a> returns a new\n<code>Buffer</code> that <em>contains a copy</em> of the provided string.</li>\n<li><a href=\"#buffer_class_method_buffer_alloc_size_fill_encoding\"><code>Buffer.alloc(size[, fill[, encoding]])</code></a> returns a new\ninitialized <code>Buffer</code> of the specified size. This method is slower than\n<a href=\"#buffer_class_method_buffer_allocunsafe_size\"><code>Buffer.allocUnsafe(size)</code></a> but guarantees that newly\ncreated <code>Buffer</code> instances never contain old data that is potentially\nsensitive.</li>\n<li><a href=\"#buffer_class_method_buffer_allocunsafe_size\"><code>Buffer.allocUnsafe(size)</code></a> and\n<a href=\"#buffer_class_method_buffer_allocunsafeslow_size\"><code>Buffer.allocUnsafeSlow(size)</code></a> each return a\nnew uninitialized <code>Buffer</code> of the specified <code>size</code>. Because the <code>Buffer</code> is\nuninitialized, the allocated segment of memory might contain old data that is\npotentially sensitive.</li>\n</ul>\n<p><code>Buffer</code> instances returned by <a href=\"#buffer_class_method_buffer_allocunsafe_size\"><code>Buffer.allocUnsafe()</code></a> <em>may</em> be allocated off\na shared internal memory pool if <code>size</code> is less than or equal to half\n<a href=\"#buffer_class_property_buffer_poolsize\"><code>Buffer.poolSize</code></a>. Instances returned by <a href=\"#buffer_class_method_buffer_allocunsafeslow_size\"><code>Buffer.allocUnsafeSlow()</code></a> <em>never</em>\nuse the shared internal memory pool.</p>\n",
"modules": [
{
"textRaw": "The `--zero-fill-buffers` command line option",
"name": "the_`--zero-fill-buffers`_command_line_option",
"meta": {
"added": [
"v5.10.0"
],
"changes": []
},
"desc": "<p>Node.js can be started using the <code>--zero-fill-buffers</code> command line option to\ncause all newly allocated <code>Buffer</code> instances to be zero-filled upon creation by\ndefault, including buffers returned by <code>new Buffer(size)</code>,\n<a href=\"#buffer_class_method_buffer_allocunsafe_size\"><code>Buffer.allocUnsafe()</code></a>, <a href=\"#buffer_class_method_buffer_allocunsafeslow_size\"><code>Buffer.allocUnsafeSlow()</code></a>, and <code>new\nSlowBuffer(size)</code>. Use of this flag can have a significant negative impact on\nperformance. Use of the <code>--zero-fill-buffers</code> option is recommended only when\nnecessary to enforce that newly allocated <code>Buffer</code> instances cannot contain old\ndata that is potentially sensitive.</p>\n<pre><code class=\"lang-txt\">$ node --zero-fill-buffers\n> Buffer.allocUnsafe(5);\n<Buffer 00 00 00 00 00>\n</code></pre>\n",
"type": "module",
"displayName": "The `--zero-fill-buffers` command line option"
},
{
"textRaw": "What makes `Buffer.allocUnsafe()` and `Buffer.allocUnsafeSlow()` \"unsafe\"?",
"name": "what_makes_`buffer.allocunsafe()`_and_`buffer.allocunsafeslow()`_\"unsafe\"?",
"desc": "<p>When calling <a href=\"#buffer_class_method_buffer_allocunsafe_size\"><code>Buffer.allocUnsafe()</code></a> and <a href=\"#buffer_class_method_buffer_allocunsafeslow_size\"><code>Buffer.allocUnsafeSlow()</code></a>, the\nsegment of allocated memory is <em>uninitialized</em> (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 <code>Buffer</code>\ncreated by <a href=\"#buffer_class_method_buffer_allocunsafe_size\"><code>Buffer.allocUnsafe()</code></a> without <em>completely</em> overwriting the memory\ncan allow this old data to be leaked when the <code>Buffer</code> memory is read.</p>\n<p>While there are clear performance advantages to using <a href=\"#buffer_class_method_buffer_allocunsafe_size\"><code>Buffer.allocUnsafe()</code></a>,\nextra care <em>must</em> be taken in order to avoid introducing security\nvulnerabilities into an application.</p>\n",
"type": "module",
"displayName": "What makes `Buffer.allocUnsafe()` and `Buffer.allocUnsafeSlow()` \"unsafe\"?"
}
],
"type": "module",
"displayName": "`Buffer.from()`, `Buffer.alloc()`, and `Buffer.allocUnsafe()`"
},
{
"textRaw": "Buffers and Character Encodings",
"name": "buffers_and_character_encodings",
"meta": {
"changes": [
{
"version": "v6.4.0",
"pr-url": "https://github.com/nodejs/node/pull/7111",
"description": "Introduced `latin1` as an alias for `binary`."
},
{
"version": "v5.0.0",
"pr-url": "https://github.com/nodejs/node/pull/2859",
"description": "Removed the deprecated `raw` and `raws` encodings."
}
]
},
"desc": "<p>When string data is stored in or extracted out of a <code>Buffer</code> instance, a\ncharacter encoding may be specified.</p>\n<pre><code class=\"lang-js\">const buf = Buffer.from('hello world', 'ascii');\n\nconsole.log(buf.toString('hex'));\n// Prints: 68656c6c6f20776f726c64\nconsole.log(buf.toString('base64'));\n// Prints: aGVsbG8gd29ybGQ=\n\nconsole.log(Buffer.from('fhqwhgads', 'ascii'));\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>\n</code></pre>\n<p>The character encodings currently supported by Node.js include:</p>\n<ul>\n<li><p><code>'ascii'</code> - For 7-bit ASCII data only. This encoding is fast and will strip\nthe high bit if set.</p>\n</li>\n<li><p><code>'utf8'</code> - Multibyte encoded Unicode characters. Many web pages and other\ndocument formats use UTF-8.</p>\n</li>\n<li><p><code>'utf16le'</code> - 2 or 4 bytes, little-endian encoded Unicode characters.\nSurrogate pairs (U+10000 to U+10FFFF) are supported.</p>\n</li>\n<li><p><code>'ucs2'</code> - Alias of <code>'utf16le'</code>.</p>\n</li>\n<li><p><code>'base64'</code> - Base64 encoding. When creating a <code>Buffer</code> from a string,\nthis encoding will also correctly accept "URL and Filename Safe Alphabet" as\nspecified in <a href=\"https://tools.ietf.org/html/rfc4648#section-5\">RFC4648, Section 5</a>.</p>\n</li>\n<li><p><code>'latin1'</code> - A way of encoding the <code>Buffer</code> into a one-byte encoded string\n(as defined by the IANA in <a href=\"https://tools.ietf.org/html/rfc1345\">RFC1345</a>,\npage 63, to be the Latin-1 supplement block and C0/C1 control codes).</p>\n</li>\n<li><p><code>'binary'</code> - Alias for <code>'latin1'</code>.</p>\n</li>\n<li><p><code>'hex'</code> - Encode each byte as two hexadecimal characters.</p>\n</li>\n</ul>\n<p>Modern Web browsers follow the <a href=\"https://encoding.spec.whatwg.org/\">WHATWG Encoding Standard</a> which aliases\nboth <code>'latin1'</code> and <code>'ISO-8859-1'</code> to <code>'win-1252'</code>. This means that while doing\nsomething like <code>http.get()</code>, if the returned charset is one of those listed in\nthe WHATWG specification it is possible that the server actually returned\nwin-1252-encoded data, and using <code>'latin1'</code> encoding may incorrectly decode the\ncharacters.</p>\n",
"type": "module",
"displayName": "Buffers and Character Encodings"
},
{
"textRaw": "Buffers and TypedArray",
"name": "buffers_and_typedarray",
"meta": {
"changes": [
{
"version": "v3.0.0",
"pr-url": "https://github.com/nodejs/node/pull/2002",
"description": "The `Buffer`s class now inherits from `Uint8Array`."
}
]
},
"desc": "<p><code>Buffer</code> instances are also <a href=\"https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint8Array\"><code>Uint8Array</code></a> instances. However, there are subtle\nincompatibilities with <a href=\"https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray\"><code>TypedArray</code></a>. For example, while\n<a href=\"https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer/slice\"><code>ArrayBuffer#slice()</code></a> creates a copy of the slice, the implementation of\n<a href=\"#buffer_buf_slice_start_end\"><code>Buffer#slice()</code></a> creates a view over the existing <code>Buffer</code>\nwithout copying, making <a href=\"#buffer_buf_slice_start_end\"><code>Buffer#slice()</code></a> far more efficient.</p>\n<p>It is also possible to create new <a href=\"https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray\"><code>TypedArray</code></a> instances from a <code>Buffer</code> with\nthe following caveats:</p>\n<ol>\n<li><p>The <code>Buffer</code> object's memory is copied to the <a href=\"https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray\"><code>TypedArray</code></a>, not shared.</p>\n</li>\n<li><p>The <code>Buffer</code> object's memory is interpreted as an array of distinct\nelements, and not as a byte array of the target type. That is,\n<code>new Uint32Array(Buffer.from([1, 2, 3, 4]))</code> creates a 4-element <a href=\"https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint32Array\"><code>Uint32Array</code></a>\nwith elements <code>[1, 2, 3, 4]</code>, not a <a href=\"https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint32Array\"><code>Uint32Array</code></a> with a single element\n<code>[0x1020304]</code> or <code>[0x4030201]</code>.</p>\n</li>\n</ol>\n<p>It is possible to create a new <code>Buffer</code> that shares the same allocated memory as\na <a href=\"https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray\"><code>TypedArray</code></a> instance by using the TypeArray object's <code>.buffer</code> property.</p>\n<pre><code class=\"lang-js\">const arr = new Uint16Array(2);\n\narr[0] = 5000;\narr[1] = 4000;\n\n// Copies the contents of `arr`\nconst buf1 = Buffer.from(arr);\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>\n</code></pre>\n<p>Note that when creating a <code>Buffer</code> using a <a href=\"https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray\"><code>TypedArray</code></a>'s <code>.buffer</code>, it is\npossible to use only a portion of the underlying <a href=\"https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer\"><code>ArrayBuffer</code></a> by passing in\n<code>byteOffset</code> and <code>length</code> parameters.</p>\n<pre><code class=\"lang-js\">const arr = new Uint16Array(20);\nconst buf = Buffer.from(arr.buffer, 0, 16);\n\nconsole.log(buf.length);\n// Prints: 16\n</code></pre>\n<p>The <code>Buffer.from()</code> and <a href=\"https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/from\"><code>TypedArray.from()</code></a> have different signatures and\nimplementations. Specifically, the <a href=\"https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray\"><code>TypedArray</code></a> variants accept a second\nargument that is a mapping function that is invoked on every element of the\ntyped array:</p>\n<ul>\n<li><code>TypedArray.from(source[, mapFn[, thisArg]])</code></li>\n</ul>\n<p>The <code>Buffer.from()</code> method, however, does not support the use of a mapping\nfunction:</p>\n<ul>\n<li><a href=\"#buffer_class_method_buffer_from_array\"><code>Buffer.from(array)</code></a></li>\n<li><a href=\"#buffer_class_method_buffer_from_buffer\"><code>Buffer.from(buffer)</code></a></li>\n<li><a href=\"#buffer_class_method_buffer_from_arraybuffer_byteoffset_length\"><code>Buffer.from(arrayBuffer[, byteOffset [, length]])</code></a></li>\n<li><a href=\"#buffer_class_method_buffer_from_string_encoding\"><code>Buffer.from(string[, encoding])</code></a></li>\n</ul>\n",
"type": "module",
"displayName": "Buffers and TypedArray"
},
{
"textRaw": "Buffers and iteration",
"name": "buffers_and_iteration",
"desc": "<p><code>Buffer</code> instances can be iterated over using <code>for..of</code> syntax:</p>\n<pre><code class=\"lang-js\">const buf = Buffer.from([1, 2, 3]);\n\n// Prints:\n// 1\n// 2\n// 3\nfor (const b of buf) {\n console.log(b);\n}\n</code></pre>\n<p>Additionally, the <a href=\"#buffer_buf_values\"><code>buf.values()</code></a>, <a href=\"#buffer_buf_keys\"><code>buf.keys()</code></a>, and\n<a href=\"#buffer_buf_entries\"><code>buf.entries()</code></a> methods can be used to create iterators.</p>\n",
"type": "module",
"displayName": "Buffers and iteration"
},
{
"textRaw": "Buffer Constants",
"name": "buffer_constants",
"meta": {
"added": [
"v8.2.0"
],
"changes": []
},
"desc": "<p>Note that <code>buffer.constants</code> is a property on the <code>buffer</code> module returned by\n<code>require('buffer')</code>, not on the <code>Buffer</code> global or a <code>Buffer</code> instance.</p>\n",
"modules": [
{
"textRaw": "buffer.constants.MAX_LENGTH",
"name": "buffer.constants.max_length",
"meta": {
"added": [
"v8.2.0"
],
"changes": []
},
"desc": "<ul>\n<li>{integer} The largest size allowed for a single <code>Buffer</code> instance.</li>\n</ul>\n<p>On 32-bit architectures, this value is <code>(2^30)-1</code> (~1GB).\nOn 64-bit architectures, this value is <code>(2^31)-1</code> (~2GB).</p>\n<p>This value is also available as <a href=\"#buffer_buffer_kmaxlength\"><code>buffer.kMaxLength</code></a>.</p>\n",
"type": "module",
"displayName": "buffer.constants.MAX_LENGTH"
},
{
"textRaw": "buffer.constants.MAX_STRING_LENGTH",
"name": "buffer.constants.max_string_length",
"meta": {
"added": [
"v8.2.0"
],
"changes": []
},
"desc": "<ul>\n<li>{integer} The largest length allowed for a single <code>string</code> instance.</li>\n</ul>\n<p>Represents the largest <code>length</code> that a <code>string</code> primitive can have, counted\nin UTF-16 code units.</p>\n<p>This value may depend on the JS engine that is being used.</p>\n",
"type": "module",
"displayName": "buffer.constants.MAX_STRING_LENGTH"
}
],
"type": "module",
"displayName": "Buffer Constants"
}
],
"classes": [
{
"textRaw": "Class: Buffer",
"type": "class",
"name": "Buffer",
"desc": "<p>The <code>Buffer</code> class is a global type for dealing with binary data directly.\nIt can be constructed in a variety of ways.</p>\n",
"classMethods": [
{
"textRaw": "Class Method: Buffer.alloc(size[, fill[, encoding]])",
"type": "classMethod",
"name": "alloc",
"meta": {
"added": [
"v5.10.0"
],
"changes": [
{
"version": "v9.2.1",
"pr-url": "https://github.com/nodejs/node/pull/17428",
"description": "Specifying an invalid string for `fill` now results in a zero-filled buffer."
}
]
},
"signatures": [
{
"params": [
{
"textRaw": "`size` {integer} The desired length of the new `Buffer`. ",
"name": "size",
"type": "integer",
"desc": "The desired length of the new `Buffer`."
},
{
"textRaw": "`fill` {string|Buffer|integer} A value to pre-fill the new `Buffer` with. **Default:** `0` ",
"name": "fill",
"type": "string|Buffer|integer",
"desc": "A value to pre-fill the new `Buffer` with. **Default:** `0`",
"optional": true
},
{
"textRaw": "`encoding` {string} If `fill` is a string, this is its encoding. **Default:** `'utf8'` ",
"name": "encoding",
"type": "string",
"desc": "If `fill` is a string, this is its encoding. **Default:** `'utf8'`",
"optional": true
}
]
},
{
"params": [
{
"name": "size"
},
{
"name": "fill",
"optional": true
},
{
"name": "encoding",
"optional": true
}
]
}
],
"desc": "<p>Allocates a new <code>Buffer</code> of <code>size</code> bytes. If <code>fill</code> is <code>undefined</code>, the\n<code>Buffer</code> will be <em>zero-filled</em>.</p>\n<pre><code class=\"lang-js\">const buf = Buffer.alloc(5);\n\nconsole.log(buf);\n// Prints: <Buffer 00 00 00 00 00>\n</code></pre>\n<p>Allocates a new <code>Buffer</code> of <code>size</code> bytes. If the <code>size</code> is larger than\n<a href=\"#buffer_buffer_constants_max_length\"><code>buffer.constants.MAX_LENGTH</code></a> or smaller than 0, a <a href=\"errors.html#errors_class_rangeerror\"><code>RangeError</code></a> will be\nthrown. A zero-length <code>Buffer</code> will be created if <code>size</code> is 0.</p>\n<p>If <code>fill</code> is specified, the allocated <code>Buffer</code> will be initialized by calling\n<a href=\"#buffer_buf_fill_value_offset_end_encoding\"><code>buf.fill(fill)</code></a>.</p>\n<pre><code class=\"lang-js\">const buf = Buffer.alloc(5, 'a');\n\nconsole.log(buf);\n// Prints: <Buffer 61 61 61 61 61>\n</code></pre>\n<p>If both <code>fill</code> and <code>encoding</code> are specified, the allocated <code>Buffer</code> will be\ninitialized by calling <a href=\"#buffer_buf_fill_value_offset_end_encoding\"><code>buf.fill(fill, encoding)</code></a>.</p>\n<pre><code class=\"lang-js\">const buf = Buffer.alloc(11, 'aGVsbG8gd29ybGQ=', 'base64');\n\nconsole.log(buf);\n// Prints: <Buffer 68 65 6c 6c 6f 20 77 6f 72 6c 64>\n</code></pre>\n<p>Calling <a href=\"#buffer_class_method_buffer_alloc_size_fill_encoding\"><code>Buffer.alloc()</code></a> can be significantly slower than the alternative\n<a href=\"#buffer_class_method_buffer_allocunsafe_size\"><code>Buffer.allocUnsafe()</code></a> but ensures that the newly created <code>Buffer</code> instance\ncontents will <em>never contain sensitive data</em>.</p>\n<p>A <code>TypeError</code> will be thrown if <code>size</code> is not a number.</p>\n"
},
{
"textRaw": "Class Method: Buffer.allocUnsafe(size)",
"type": "classMethod",
"name": "allocUnsafe",
"meta": {
"added": [
"v5.10.0"
],
"changes": [
{
"version": "v7.0.0",
"pr-url": "https://github.com/nodejs/node/pull/7079",
"description": "Passing a negative `size` will now throw an error."
}
]
},
"signatures": [
{
"params": [
{
"textRaw": "`size` {integer} The desired length of the new `Buffer`. ",
"name": "size",
"type": "integer",
"desc": "The desired length of the new `Buffer`."
}
]
},
{
"params": [
{
"name": "size"
}
]
}
],
"desc": "<p>Allocates a new <code>Buffer</code> of <code>size</code> bytes. If the <code>size</code> is larger than\n<a href=\"#buffer_buffer_constants_max_length\"><code>buffer.constants.MAX_LENGTH</code></a> or smaller than 0, a <a href=\"errors.html#errors_class_rangeerror\"><code>RangeError</code></a> will be\nthrown. A zero-length <code>Buffer</code> will be created if <code>size</code> is 0.</p>\n<p>The underlying memory for <code>Buffer</code> instances created in this way is <em>not\ninitialized</em>. The contents of the newly created <code>Buffer</code> are unknown and\n<em>may contain sensitive data</em>. Use <a href=\"#buffer_class_method_buffer_alloc_size_fill_encoding\"><code>Buffer.alloc()</code></a> instead to initialize\n<code>Buffer</code> instances with zeroes.</p>\n<pre><code class=\"lang-js\">const 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>\n</code></pre>\n<p>A <code>TypeError</code> will be thrown if <code>size</code> is not a number.</p>\n<p>Note that the <code>Buffer</code> module pre-allocates an internal <code>Buffer</code> instance of\nsize <a href=\"#buffer_class_property_buffer_poolsize\"><code>Buffer.poolSize</code></a> that is used as a pool for the fast allocation of new\n<code>Buffer</code> instances created using <a href=\"#buffer_class_method_buffer_allocunsafe_size\"><code>Buffer.allocUnsafe()</code></a> and the deprecated\n<code>new Buffer(size)</code> constructor only when <code>size</code> is less than or equal to\n<code>Buffer.poolSize >> 1</code> (floor of <a href=\"#buffer_class_property_buffer_poolsize\"><code>Buffer.poolSize</code></a> divided by two).</p>\n<p>Use of this pre-allocated internal memory pool is a key difference between\ncalling <code>Buffer.alloc(size, fill)</code> vs. <code>Buffer.allocUnsafe(size).fill(fill)</code>.\nSpecifically, <code>Buffer.alloc(size, fill)</code> will <em>never</em> use the internal <code>Buffer</code>\npool, while <code>Buffer.allocUnsafe(size).fill(fill)</code> <em>will</em> use the internal\n<code>Buffer</code> pool if <code>size</code> is less than or equal to half <a href=\"#buffer_class_property_buffer_poolsize\"><code>Buffer.poolSize</code></a>. The\ndifference is subtle but can be important when an application requires the\nadditional performance that <a href=\"#buffer_class_method_buffer_allocunsafe_size\"><code>Buffer.allocUnsafe()</code></a> provides.</p>\n"
},
{
"textRaw": "Class Method: Buffer.allocUnsafeSlow(size)",
"type": "classMethod",
"name": "allocUnsafeSlow",
"meta": {
"added": [
"v5.12.0"
],
"changes": []
},
"signatures": [
{
"params": [
{
"textRaw": "`size` {integer} The desired length of the new `Buffer`. ",
"name": "size",
"type": "integer",
"desc": "The desired length of the new `Buffer`."
}
]
},
{
"params": [
{
"name": "size"
}
]
}
],
"desc": "<p>Allocates a new <code>Buffer</code> of <code>size</code> bytes. If the <code>size</code> is larger than\n<a href=\"#buffer_buffer_constants_max_length\"><code>buffer.constants.MAX_LENGTH</code></a> or smaller than 0, a <a href=\"errors.html#errors_class_rangeerror\"><code>RangeError</code></a> will be\nthrown. A zero-length <code>Buffer</code> will be created if <code>size</code> is 0.</p>\n<p>The underlying memory for <code>Buffer</code> instances created in this way is <em>not\ninitialized</em>. The contents of the newly created <code>Buffer</code> are unknown and\n<em>may contain sensitive data</em>. Use <a href=\"#buffer_buf_fill_value_offset_end_encoding\"><code>buf.fill(0)</code></a> to initialize\nsuch <code>Buffer</code> instances with zeroes.</p>\n<p>When using <a href=\"#buffer_class_method_buffer_allocunsafe_size\"><code>Buffer.allocUnsafe()</code></a> to allocate new <code>Buffer</code> instances,\nallocations under 4KB are sliced from a single pre-allocated <code>Buffer</code>. This\nallows applications to avoid the garbage collection overhead of creating many\nindividually allocated <code>Buffer</code> instances. This approach improves both\nperformance and memory usage by eliminating the need to track and clean up as\nmany persistent objects.</p>\n<p>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 <code>Buffer</code> instance using <code>Buffer.allocUnsafeSlow()</code> and\nthen copying out the relevant bits.</p>\n<pre><code class=\"lang-js\">// Need to keep around a few small chunks of memory\nconst store = [];\n\nsocket.on('readable', () => {\n const data = socket.read();\n\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</code></pre>\n<p><code>Buffer.allocUnsafeSlow()</code> should be used only as a last resort after a\ndeveloper has observed undue memory retention in their applications.</p>\n<p>A <code>TypeError</code> will be thrown if <code>size</code> is not a number.</p>\n"
},
{
"textRaw": "Class Method: Buffer.byteLength(string[, encoding])",
"type": "classMethod",
"name": "byteLength",
"meta": {
"added": [
"v0.1.90"
],
"changes": [
{
"version": "v7.0.0",
"pr-url": "https://github.com/nodejs/node/pull/8946",
"description": "Passing invalid input will now throw an error."
},
{
"version": "v5.10.0",
"pr-url": "https://github.com/nodejs/node/pull/5255",
"description": "The `string` parameter can now be any `TypedArray`, `DataView` or `ArrayBuffer`."
}
]
},
"signatures": [
{
"return": {
"textRaw": "Returns: {integer} The number of bytes contained within `string`. ",
"name": "return",
"type": "integer",
"desc": "The number of bytes contained within `string`."
},
"params": [
{
"textRaw": "`string` {string|Buffer|TypedArray|DataView|ArrayBuffer|SharedArrayBuffer} A value to calculate the length of. ",
"name": "string",
"type": "string|Buffer|TypedArray|DataView|ArrayBuffer|SharedArrayBuffer",
"desc": "A value to calculate the length of."
},
{
"textRaw": "`encoding` {string} If `string` is a string, this is its encoding. **Default:** `'utf8'` ",
"name": "encoding",
"type": "string",
"desc": "If `string` is a string, this is its encoding. **Default:** `'utf8'`",
"optional": true
}
]
},
{
"params": [
{
"name": "string"
},
{
"name": "encoding",
"optional": true
}
]
}
],
"desc": "<p>Returns the actual byte length of a string. This is not the same as\n<a href=\"https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/length\"><code>String.prototype.length</code></a> since that returns the number of <em>characters</em> in\na string.</p>\n<p>For <code>'base64'</code> and <code>'hex'</code>, this function assumes valid input. For strings that\ncontain non-Base64/Hex-encoded data (e.g. whitespace), the return value might be\ngreater than the length of a <code>Buffer</code> created from the string.</p>\n<pre><code class=\"lang-js\">const 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\n</code></pre>\n<p>When <code>string</code> is a <code>Buffer</code>/<a href=\"https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DataView\"><code>DataView</code></a>/<a href=\"https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray\"><code>TypedArray</code></a>/<a href=\"https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer\"><code>ArrayBuffer</code></a>/\n<a href=\"https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/SharedArrayBuffer\"><code>SharedArrayBuffer</code></a>, the actual byte length is returned.</p>\n"
},
{
"textRaw": "Class Method: Buffer.compare(buf1, buf2)",
"type": "classMethod",
"name": "compare",
"meta": {
"added": [
"v0.11.13"
],
"changes": [
{
"version": "v8.0.0",
"pr-url": "https://github.com/nodejs/node/pull/10236",
"description": "The arguments can now be `Uint8Array`s."
}
]
},
"signatures": [
{
"return": {
"textRaw": "Returns: {integer} ",
"name": "return",
"type": "integer"
},
"params": [
{
"textRaw": "`buf1` {Buffer|Uint8Array} ",
"name": "buf1",
"type": "Buffer|Uint8Array"
},
{
"textRaw": "`buf2` {Buffer|Uint8Array} ",
"name": "buf2",
"type": "Buffer|Uint8Array"
}
]
},
{
"params": [
{
"name": "buf1"
},
{
"name": "buf2"
}
]
}
],
"desc": "<p>Compares <code>buf1</code> to <code>buf2</code> typically for the purpose of sorting arrays of\n<code>Buffer</code> instances. This is equivalent to calling\n<a href=\"#buffer_buf_compare_target_targetstart_targetend_sourcestart_sourceend\"><code>buf1.compare(buf2)</code></a>.</p>\n<pre><code class=\"lang-js\">const 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])\n</code></pre>\n"
},
{
"textRaw": "Class Method: Buffer.concat(list[, totalLength])",
"type": "classMethod",
"name": "concat",
"meta": {
"added": [
"v0.7.11"
],
"changes": [
{
"version": "v8.0.0",
"pr-url": "https://github.com/nodejs/node/pull/10236",
"description": "The elements of `list` can now be `Uint8Array`s."
}
]
},
"signatures": [
{
"return": {
"textRaw": "Returns: {Buffer} ",
"name": "return",
"type": "Buffer"
},
"params": [
{
"textRaw": "`list` {Array} List of `Buffer` or [`Uint8Array`] instances to concat. ",
"name": "list",
"type": "Array",
"desc": "List of `Buffer` or [`Uint8Array`] instances to concat."
},
{
"textRaw": "`totalLength` {integer} Total length of the `Buffer` instances in `list` when concatenated. ",
"name": "totalLength",
"type": "integer",
"desc": "Total length of the `Buffer` instances in `list` when concatenated.",
"optional": true
}
]
},
{
"params": [
{
"name": "list"
},
{
"name": "totalLength",
"optional": true
}
]
}
],
"desc": "<p>Returns a new <code>Buffer</code> which is the result of concatenating all the <code>Buffer</code>\ninstances in the <code>list</code> together.</p>\n<p>If the list has no items, or if the <code>totalLength</code> is 0, then a new zero-length\n<code>Buffer</code> is returned.</p>\n<p>If <code>totalLength</code> is not provided, it is calculated from the <code>Buffer</code> instances\nin <code>list</code>. This however causes an additional loop to be executed in order to\ncalculate the <code>totalLength</code>, so it is faster to provide the length explicitly if\nit is already known.</p>\n<p>If <code>totalLength</code> is provided, it is coerced to an unsigned integer. If the\ncombined length of the <code>Buffer</code>s in <code>list</code> exceeds <code>totalLength</code>, the result is\ntruncated to <code>totalLength</code>.</p>\n<pre><code class=\"lang-js\">// 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\n</code></pre>\n"
},
{
"textRaw": "Class Method: Buffer.from(array)",
"type": "classMethod",
"name": "from",
"meta": {
"added": [
"v5.10.0"
],
"changes": []
},
"signatures": [
{
"params": [
{
"textRaw": "`array` {Array} ",
"name": "array",
"type": "Array"
}
]
},
{
"params": [
{
"name": "array"
}
]
}
],
"desc": "<p>Allocates a new <code>Buffer</code> using an <code>array</code> of octets.</p>\n<pre><code class=\"lang-js\">// Creates a new Buffer containing UTF-8 bytes of the string 'buffer'\nconst buf = Buffer.from([0x62, 0x75, 0x66, 0x66, 0x65, 0x72]);\n</code></pre>\n<p>A <code>TypeError</code> will be thrown if <code>array</code> is not an <code>Array</code>.</p>\n"
},
{
"textRaw": "Class Method: Buffer.from(arrayBuffer[, byteOffset[, length]])",
"type": "classMethod",
"name": "from",
"meta": {
"added": [
"v5.10.0"
],
"changes": []
},
"signatures": [
{
"params": [
{
"textRaw": "`arrayBuffer` {ArrayBuffer|SharedArrayBuffer} An [`ArrayBuffer`], [`SharedArrayBuffer`], or the `.buffer` property of a [`TypedArray`]. ",
"name": "arrayBuffer",
"type": "ArrayBuffer|SharedArrayBuffer",
"desc": "An [`ArrayBuffer`], [`SharedArrayBuffer`], or the `.buffer` property of a [`TypedArray`]."
},
{
"textRaw": "`byteOffset` {integer} Index of first byte to expose. **Default:** `0` ",
"name": "byteOffset",
"type": "integer",
"desc": "Index of first byte to expose. **Default:** `0`",
"optional": true
},
{
"textRaw": "`length` {integer} Number of bytes to expose. **Default:** `arrayBuffer.length - byteOffset` ",
"name": "length",
"type": "integer",
"desc": "Number of bytes to expose. **Default:** `arrayBuffer.length - byteOffset`",
"optional": true
}
]
},
{
"params": [
{
"name": "arrayBuffer"
},
{
"name": "byteOffset",
"optional": true
},
{
"name": "length",
"optional": true
}
]
}
],
"desc": "<p>This creates a view of the <a href=\"https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer\"><code>ArrayBuffer</code></a> without copying the underlying\nmemory. For example, when passed a reference to the <code>.buffer</code> property of a\n<a href=\"https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray\"><code>TypedArray</code></a> instance, the newly created <code>Buffer</code> will share the same\nallocated memory as the <a href=\"https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray\"><code>TypedArray</code></a>.</p>\n<pre><code class=\"lang-js\">const 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>\n</code></pre>\n<p>The optional <code>byteOffset</code> and <code>length</code> arguments specify a memory range within\nthe <code>arrayBuffer</code> that will be shared by the <code>Buffer</code>.</p>\n<pre><code class=\"lang-js\">const ab = new ArrayBuffer(10);\nconst buf = Buffer.from(ab, 0, 2);\n\nconsole.log(buf.length);\n// Prints: 2\n</code></pre>\n<p>A <code>TypeError</code> will be thrown if <code>arrayBuffer</code> is not an <a href=\"https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer\"><code>ArrayBuffer</code></a> or a\n<a href=\"https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/SharedArrayBuffer\"><code>SharedArrayBuffer</code></a>.</p>\n"
},
{
"textRaw": "Class Method: Buffer.from(buffer)",
"type": "classMethod",
"name": "from",
"meta": {
"added": [
"v5.10.0"
],
"changes": []
},
"signatures": [
{
"params": [
{
"textRaw": "`buffer` {Buffer} An existing `Buffer` to copy data from. ",
"name": "buffer",
"type": "Buffer",
"desc": "An existing `Buffer` to copy data from."
}
]
},
{
"params": [
{
"name": "buffer"
}
]
}
],
"desc": "<p>Copies the passed <code>buffer</code> data onto a new <code>Buffer</code> instance.</p>\n<pre><code class=\"lang-js\">const 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\n</code></pre>\n<p>A <code>TypeError</code> will be thrown if <code>buffer</code> is not a <code>Buffer</code>.</p>\n"
},
{
"textRaw": "Class Method: Buffer.from(string[, encoding])",
"type": "classMethod",
"name": "from",
"meta": {
"added": [
"v5.10.0"
],
"changes": []
},
"signatures": [
{
"params": [
{
"textRaw": "`string` {string} A string to encode. ",
"name": "string",
"type": "string",
"desc": "A string to encode."
},
{
"textRaw": "`encoding` {string} The encoding of `string`. **Default:** `'utf8'` ",
"name": "encoding",
"type": "string",
"desc": "The encoding of `string`. **Default:** `'utf8'`",
"optional": true
}
]
},
{
"params": [
{
"name": "string"
},
{
"name": "encoding",
"optional": true
}
]
}
],
"desc": "<p>Creates a new <code>Buffer</code> containing <code>string</code>. The <code>encoding</code> parameter identifies\nthe character encoding of <code>string</code>.</p>\n<pre><code class=\"lang-js\">const 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('ascii'));\n// Prints: this is a tC)st\n</code></pre>\n<p>A <code>TypeError</code> will be thrown if <code>string</code> is not a string.</p>\n"
},
{
"textRaw": "Class Method: Buffer.from(object[, offsetOrEncoding[, length]])",
"type": "classMethod",
"name": "from",
"meta": {
"added": [
"v8.2.0"
],
"changes": []
},
"signatures": [
{
"params": [
{
"textRaw": "`object` {Object} An object supporting `Symbol.toPrimitive` or `valueOf()` ",
"name": "object",
"type": "Object",
"desc": "An object supporting `Symbol.toPrimitive` or `valueOf()`"
},
{
"textRaw": "`offsetOrEncoding` {number|string} A byte-offset or encoding, depending on the value returned either by `object.valueOf()` or `object[Symbol.toPrimitive]()`. ",
"name": "offsetOrEncoding",
"type": "number|string",
"desc": "A byte-offset or encoding, depending on the value returned either by `object.valueOf()` or `object[Symbol.toPrimitive]()`.",
"optional": true
},
{
"textRaw": "`length` {number} A length, depending on the value returned either by `object.valueOf()` or `object[Symbol.toPrimitive]()`. ",
"name": "length",
"type": "number",
"desc": "A length, depending on the value returned either by `object.valueOf()` or `object[Symbol.toPrimitive]()`.",
"optional": true
}
]
},
{
"params": [
{
"name": "object"
},
{
"name": "offsetOrEncoding",
"optional": true
},
{
"name": "length",
"optional": true
}
]
}
],
"desc": "<p>For objects whose <code>valueOf()</code> function returns a value not strictly equal to\n<code>object</code>, returns <code>Buffer.from(object.valueOf(), offsetOrEncoding, length)</code>.</p>\n<pre><code class=\"lang-js\">const 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>\n</code></pre>\n<p>For objects that support <code>Symbol.toPrimitive</code>, returns\n<code>Buffer.from(object[Symbol.toPrimitive](), offsetOrEncoding, length)</code>.</p>\n<pre><code class=\"lang-js\">class 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>\n</code></pre>\n"
},
{
"textRaw": "Class Method: Buffer.isBuffer(obj)",
"type": "classMethod",
"name": "isBuffer",
"meta": {
"added": [
"v0.1.101"
],
"changes": []
},
"signatures": [
{
"return": {
"textRaw": "Returns: {boolean} ",
"name": "return",
"type": "boolean"
},
"params": [
{
"textRaw": "`obj` {Object} ",
"name": "obj",
"type": "Object"
}
]
},
{
"params": [
{
"name": "obj"
}
]
}
],
"desc": "<p>Returns <code>true</code> if <code>obj</code> is a <code>Buffer</code>, <code>false</code> otherwise.</p>\n"
},
{
"textRaw": "Class Method: Buffer.isEncoding(encoding)",
"type": "classMethod",
"name": "isEncoding",
"meta": {
"added": [
"v0.9.1"
],
"changes": []
},
"signatures": [
{
"return": {
"textRaw": "Returns: {boolean} ",
"name": "return",
"type": "boolean"
},
"params": [
{
"textRaw": "`encoding` {string} A character encoding name to check. ",
"name": "encoding",
"type": "string",
"desc": "A character encoding name to check."
}
]
},
{
"params": [
{
"name": "encoding"
}
]
}
],
"desc": "<p>Returns <code>true</code> if <code>encoding</code> contains a supported character encoding, or <code>false</code>\notherwise.</p>\n"
}
],
"properties": [
{
"textRaw": "`poolSize` {integer} **Default:** `8192` ",
"type": "integer",
"name": "poolSize",
"meta": {
"added": [
"v0.11.3"
],
"changes": []
},
"desc": "<p>This is the number of bytes used to determine the size of pre-allocated, internal\n<code>Buffer</code> instances used for pooling. This value may be modified.</p>\n",
"shortDesc": "**Default:** `8192`"
},
{
"textRaw": "buf[index]",
"name": "[index]",
"meta": {
"type": "property",
"name": [
"index"
],
"changes": []
},
"desc": "<p>The index operator <code>[index]</code> can be used to get and set the octet at position\n<code>index</code> in <code>buf</code>. The values refer to individual bytes, so the legal value\nrange is between <code>0x00</code> and <code>0xFF</code> (hex) or <code>0</code> and <code>255</code> (decimal).</p>\n<p>This operator is inherited from <code>Uint8Array</code>, so its behavior on out-of-bounds\naccess is the same as <code>UInt8Array</code> - that is, getting returns <code>undefined</code> and\nsetting does nothing.</p>\n<pre><code class=\"lang-js\">// Copy an ASCII string into a `Buffer` one byte at a time.\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('ascii'));\n// Prints: Node.js\n</code></pre>\n"
},
{
"textRaw": "buf.buffer",
"name": "buffer",
"desc": "<p>The <code>buffer</code> property references the underlying <code>ArrayBuffer</code> object based on\nwhich this Buffer object is created.</p>\n<pre><code class=\"lang-js\">const arrayBuffer = new ArrayBuffer(16);\nconst buffer = Buffer.from(arrayBuffer);\n\nconsole.log(buffer.buffer === arrayBuffer);\n// Prints: true\n</code></pre>\n"
},
{
"textRaw": "`length` {integer} ",
"type": "integer",
"name": "length",
"meta": {
"added": [
"v0.1.90"
],
"changes": []
},
"desc": "<p>Returns the amount of memory allocated for <code>buf</code> in bytes. Note that this\ndoes not necessarily reflect the amount of "usable" data within <code>buf</code>.</p>\n<pre><code class=\"lang-js\">// Create a `Buffer` and write a shorter ASCII string to it.\n\nconst buf = Buffer.alloc(1234);\n\nconsole.log(buf.length);\n// Prints: 1234\n\nbuf.write('some string', 0, 'ascii');\n\nconsole.log(buf.length);\n// Prints: 1234\n</code></pre>\n<p>While the <code>length</code> property is not immutable, changing the value of <code>length</code>\ncan result in undefined and inconsistent behavior. Applications that wish to\nmodify the length of a <code>Buffer</code> should therefore treat <code>length</code> as read-only and\nuse <a href=\"#buffer_buf_slice_start_end\"><code>buf.slice()</code></a> to create a new <code>Buffer</code>.</p>\n<pre><code class=\"lang-js\">let buf = Buffer.allocUnsafe(10);\n\nbuf.write('abcdefghj', 0, 'ascii');\n\nconsole.log(buf.length);\n// Prints: 10\n\nbuf = buf.slice(0, 5);\n\nconsole.log(buf.length);\n// Prints: 5\n</code></pre>\n"
},
{
"textRaw": "buf.parent",
"name": "parent",
"meta": {
"deprecated": [
"v8.0.0"
],
"changes": []
},
"stability": 0,
"stabilityText": "Deprecated: Use [`buf.buffer`] instead.",
"desc": "<p>The <code>buf.parent</code> property is a deprecated alias for <code>buf.buffer</code>.</p>\n"
}
],
"methods": [
{
"textRaw": "buf.compare(target[, targetStart[, targetEnd[, sourceStart[, sourceEnd]]]])",
"type": "method",
"name": "compare",
"meta": {
"added": [
"v0.11.13"
],
"changes": [
{
"version": "v8.0.0",
"pr-url": "https://github.com/nodejs/node/pull/10236",
"description": "The `target` parameter can now be a `Uint8Array`."
},
{
"version": "v5.11.0",
"pr-url": "https://github.com/nodejs/node/pull/5880",
"description": "Additional parameters for specifying offsets are supported now."
}
]
},
"signatures": [
{
"return": {
"textRaw": "Returns: {integer} ",
"name": "return",
"type": "integer"
},
"params": [
{
"textRaw": "`target` {Buffer|Uint8Array} A `Buffer` or [`Uint8Array`] to compare to. ",
"name": "target",
"type": "Buffer|Uint8Array",
"desc": "A `Buffer` or [`Uint8Array`] to compare to."
},
{
"textRaw": "`targetStart` {integer} The offset within `target` at which to begin comparison. **Default:** `0` ",
"name": "targetStart",
"type": "integer",
"desc": "The offset within `target` at which to begin comparison. **Default:** `0`",
"optional": true
},
{
"textRaw": "`targetEnd` {integer} The offset with `target` at which to end comparison (not inclusive). **Default:** `target.length` ",
"name": "targetEnd",
"type": "integer",
"desc": "The offset with `target` at which to end comparison (not inclusive). **Default:** `target.length`",
"optional": true
},
{
"textRaw": "`sourceStart` {integer} The offset within `buf` at which to begin comparison. **Default:** `0` ",
"name": "sourceStart",
"type": "integer",
"desc": "The offset within `buf` at which to begin comparison. **Default:** `0`",
"optional": true
},
{
"textRaw": "`sourceEnd` {integer} The offset within `buf` at which to end comparison (not inclusive). **Default:** [`buf.length`] ",
"name": "sourceEnd",
"type": "integer",
"desc": "The offset within `buf` at which to end comparison (not inclusive). **Default:** [`buf.length`]",
"optional": true
}
]
},
{
"params": [
{
"name": "target"
},
{
"name": "targetStart",
"optional": true
},
{
"name": "targetEnd",
"optional": true
},
{
"name": "sourceStart",
"optional": true
},
{
"name": "sourceEnd",
"optional": true
}
]
}
],
"desc": "<p>Compares <code>buf</code> with <code>target</code> and returns a number indicating whether <code>buf</code>\ncomes before, after, or is the same as <code>target</code> in sort order.\nComparison is based on the actual sequence of bytes in each <code>Buffer</code>.</p>\n<ul>\n<li><code>0</code> is returned if <code>target</code> is the same as <code>buf</code></li>\n<li><code>1</code> is returned if <code>target</code> should come <em>before</em> <code>buf</code> when sorted.</li>\n<li><code>-1</code> is returned if <code>target</code> should come <em>after</em> <code>buf</code> when sorted.</li>\n</ul>\n<pre><code class=\"lang-js\">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\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])\n</code></pre>\n<p>The optional <code>targetStart</code>, <code>targetEnd</code>, <code>sourceStart</code>, and <code>sourceEnd</code>\narguments can be used to limit the comparison to specific ranges within <code>target</code>\nand <code>buf</code> respectively.</p>\n<pre><code class=\"lang-js\">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\n</code></pre>\n<p>A <code>RangeError</code> will be thrown if: <code>targetStart < 0</code>, <code>sourceStart < 0</code>,\n<code>targetEnd > target.byteLength</code> or <code>sourceEnd > source.byteLength</code>.</p>\n"
},
{
"textRaw": "buf.copy(target[, targetStart[, sourceStart[, sourceEnd]]])",
"type": "method",
"name": "copy",
"meta": {
"added": [
"v0.1.90"
],
"changes": []
},
"signatures": [
{
"return": {
"textRaw": "Returns: {integer} The number of bytes copied. ",
"name": "return",
"type": "integer",
"desc": "The number of bytes copied."
},
"params": [
{
"textRaw": "`target` {Buffer|Uint8Array} A `Buffer` or [`Uint8Array`] to copy into. ",
"name": "target",
"type": "Buffer|Uint8Array",
"desc": "A `Buffer` or [`Uint8Array`] to copy into."
},
{
"textRaw": "`targetStart` {integer} The offset within `target` at which to begin copying to. **Default:** `0` ",
"name": "targetStart",
"type": "integer",
"desc": "The offset within `target` at which to begin copying to. **Default:** `0`",
"optional": true
},
{
"textRaw": "`sourceStart` {integer} The offset within `buf` at which to begin copying from. **Default:** `0` ",
"name": "sourceStart",
"type": "integer",
"desc": "The offset within `buf` at which to begin copying from. **Default:** `0`",
"optional": true
},
{
"textRaw": "`sourceEnd` {integer} The offset within `buf` at which to stop copying (not inclusive). **Default:** [`buf.length`] ",
"name": "sourceEnd",
"type": "integer",
"desc": "The offset within `buf` at which to stop copying (not inclusive). **Default:** [`buf.length`]",
"optional": true
}
]
},
{
"params": [
{
"name": "target"
},
{
"name": "targetStart",
"optional": true
},
{
"name": "sourceStart",
"optional": true
},
{
"name": "sourceEnd",
"optional": true
}
]
}
],
"desc": "<p>Copies data from a region of <code>buf</code> to a region in <code>target</code> even if the <code>target</code>\nmemory region overlaps with <code>buf</code>.</p>\n<pre><code class=\"lang-js\">// 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\nconsole.log(buf2.toString('ascii', 0, 25));\n// Prints: !!!!!!!!qrst!!!!!!!!!!!!!\n</code></pre>\n<pre><code class=\"lang-js\">// 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\n</code></pre>\n"
},
{
"textRaw": "buf.entries()",
"type": "method",
"name": "entries",
"meta": {
"added": [
"v1.1.0"
],
"changes": []
},
"signatures": [
{
"return": {
"textRaw": "Returns: {Iterator} ",
"name": "return",
"type": "Iterator"
},
"params": []
},
{
"params": []
}
],
"desc": "<p>Creates and returns an <a href=\"https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Iteration_protocols\">iterator</a> of <code>[index, byte]</code> pairs from the contents of\n<code>buf</code>.</p>\n<pre><code class=\"lang-js\">// 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]\n</code></pre>\n"
},
{
"textRaw": "buf.equals(otherBuffer)",
"type": "method",
"name": "equals",
"meta": {
"added": [
"v0.11.13"
],
"changes": [
{
"version": "v8.0.0",
"pr-url": "https://github.com/nodejs/node/pull/10236",
"description": "The arguments can now be `Uint8Array`s."
}
]
},
"signatures": [
{
"return": {
"textRaw": "Returns: {boolean} ",
"name": "return",
"type": "boolean"
},
"params": [
{
"textRaw": "`otherBuffer` {Buffer} A `Buffer` or [`Uint8Array`] to compare to. ",
"name": "otherBuffer",
"type": "Buffer",
"desc": "A `Buffer` or [`Uint8Array`] to compare to."
}
]
},
{
"params": [
{
"name": "otherBuffer"
}
]
}
],
"desc": "<p>Returns <code>true</code> if both <code>buf</code> and <code>otherBuffer</code> have exactly the same bytes,\n<code>false</code> otherwise.</p>\n<pre><code class=\"lang-js\">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\n</code></pre>\n"
},
{
"textRaw": "buf.fill(value[, offset[, end]][, encoding])",
"type": "method",
"name": "fill",
"meta": {
"added": [
"v0.5.0"
],
"changes": [
{
"version": "v5.7.0",
"pr-url": "https://github.com/nodejs/node/pull/4935",
"description": "The `encoding` parameter is supported now."
}
]
},
"signatures": [
{
"return": {
"textRaw": "Returns: {Buffer} A reference to `buf`. ",
"name": "return",
"type": "Buffer",
"desc": "A reference to `buf`."
},
"params": [
{
"textRaw": "`value` {string|Buffer|integer} The value to fill `buf` with. ",
"name": "value",
"type": "string|Buffer|integer",
"desc": "The value to fill `buf` with."
},
{
"textRaw": "`offset` {integer} Number of bytes to skip before starting to fill `buf`. **Default:** `0` ",
"name": "offset",
"type": "integer",
"desc": "Number of bytes to skip before starting to fill `buf`. **Default:** `0`",
"optional": true
},
{
"textRaw": "`end` {integer} Where to stop filling `buf` (not inclusive). **Default:** [`buf.length`] ",
"name": "end",
"type": "integer",
"desc": "Where to stop filling `buf` (not inclusive). **Default:** [`buf.length`]",
"optional": true
},
{
"textRaw": "`encoding` {string} If `value` is a string, this is its encoding. **Default:** `'utf8'` ",
"name": "encoding",
"type": "string",
"desc": "If `value` is a string, this is its encoding. **Default:** `'utf8'`",
"optional": true
}
]
},
{
"params": [
{
"name": "value"
},
{
"name": "offset",
"optional": true
},
{
"name": "end",
"optional": true
},
{
"name": "encoding",
"optional": true
}
]
}
],
"desc": "<p>Fills <code>buf</code> with the specified <code>value</code>. If the <code>offset</code> and <code>end</code> are not given,\nthe entire <code>buf</code> will be filled. This is meant to be a small simplification to\nallow the creation and filling of a <code>Buffer</code> to be done on a single line.</p>\n<pre><code class=\"lang-js\">// Fill a `Buffer` with the ASCII character 'h'.\n\nconst b = Buffer.allocUnsafe(50).fill('h');\n\nconsole.log(b.toString());\n// Prints: hhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh\n</code></pre>\n<p><code>value</code> is coerced to a <code>uint32</code> value if it is not a String or Integer.</p>\n<p>If the final write of a <code>fill()</code> operation falls on a multi-byte character,\nthen only the first bytes of that character that fit into <code>buf</code> are written.</p>\n<pre><code class=\"lang-js\">// Fill a `Buffer` with a two-byte character.\n\nconsole.log(Buffer.allocUnsafe(3).fill('\\u0222'));\n// Prints: <Buffer c8 a2 c8>\n</code></pre>\n<p>If <code>value</code> contains invalid characters, it is truncated.</p>\n<p>If no valid fill data remains, then the buffer is either zero-filled or no\nfilling is performed, depending on the input type. That behavior is dictated by\ncompatibility reasons and was changed to throwing an exception in Node.js v10,\nso it's not recommended to rely on that.</p>\n<pre><code class=\"lang-js\">const 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.\n</code></pre>\n"
},
{
"textRaw": "buf.includes(value[, byteOffset][, encoding])",
"type": "method",
"name": "includes",
"meta": {
"added": [
"v5.3.0"
],
"changes": []
},
"signatures": [
{
"return": {
"textRaw": "Returns: {boolean} `true` if `value` was found in `buf`, `false` otherwise. ",
"name": "return",
"type": "boolean",
"desc": "`true` if `value` was found in `buf`, `false` otherwise."
},
"params": [
{
"textRaw": "`value` {string|Buffer|integer} What to search for. ",
"name": "value",
"type": "string|Buffer|integer",
"desc": "What to search for."
},
{
"textRaw": "`byteOffset` {integer} Where to begin searching in `buf`. **Default:** `0` ",
"name": "byteOffset",
"type": "integer",
"desc": "Where to begin searching in `buf`. **Default:** `0`",
"optional": true
},
{
"textRaw": "`encoding` {string} If `value` is a string, this is its encoding. **Default:** `'utf8'` ",
"name": "encoding",
"type": "string",
"desc": "If `value` is a string, this is its encoding. **Default:** `'utf8'`",
"optional": true
}
]
},
{
"params": [
{
"name": "value"
},
{
"name": "byteOffset",
"optional": true
},
{
"name": "encoding",
"optional": true
}
]
}
],
"desc": "<p>Equivalent to <a href=\"#buffer_buf_indexof_value_byteoffset_encoding\"><code>buf.indexOf() !== -1</code></a>.</p>\n<pre><code class=\"lang-js\">const 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\n</code></pre>\n"
},
{
"textRaw": "buf.indexOf(value[, byteOffset][, encoding])",
"type": "method",
"name": "indexOf",
"meta": {
"added": [
"v1.5.0"
],
"changes": [
{
"version": "v8.0.0",
"pr-url": "https://github.com/nodejs/node/pull/10236",
"description": "The `value` can now be a `Uint8Array`."
},
{
"version": "v5.7.0, v4.4.0",
"pr-url": "https://github.com/nodejs/node/pull/4803",
"description": "When `encoding` is being passed, the `byteOffset` parameter is no longer required."
}
]
},
"signatures": [
{
"return": {
"textRaw": "Returns: {integer} The index of the first occurrence of `value` in `buf` or `-1` if `buf` does not contain `value`. ",
"name": "return",
"type": "integer",
"desc": "The index of the first occurrence of `value` in `buf` or `-1` if `buf` does not contain `value`."
},
"params": [
{
"textRaw": "`value` {string|Buffer|Uint8Array|integer} What to search for. ",
"name": "value",
"type": "string|Buffer|Uint8Array|integer",
"desc": "What to search for."
},
{
"textRaw": "`byteOffset` {integer} Where to begin searching in `buf`. **Default:** `0` ",
"name": "byteOffset",
"type": "integer",
"desc": "Where to begin searching in `buf`. **Default:** `0`",
"optional": true
},
{
"textRaw": "`encoding` {string} If `value` is a string, this is its encoding. **Default:** `'utf8'` ",
"name": "encoding",
"type": "string",
"desc": "If `value` is a string, this is its encoding. **Default:** `'utf8'`",
"optional": true
}
]
},
{
"params": [
{
"name": "value"
},
{
"name": "byteOffset",
"optional": true
},
{
"name": "encoding",
"optional": true
}
]
}
],
"desc": "<p>If <code>value</code> is:</p>\n<ul>\n<li>a string, <code>value</code> is interpreted according to the character encoding in\n<code>encoding</code>.</li>\n<li>a <code>Buffer</code> or <a href=\"https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint8Array\"><code>Uint8Array</code></a>, <code>value</code> will be used in its entirety.\nTo compare a partial <code>Buffer</code>, use <a href=\"#buffer_buf_slice_start_end\"><code>buf.slice()</code></a>.</li>\n<li>a number, <code>value</code> will be interpreted as an unsigned 8-bit integer\nvalue between <code>0</code> and <code>255</code>.</li>\n</ul>\n<pre><code class=\"lang-js\">const 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\n</code></pre>\n<p>If <code>value</code> is not a string, number, or <code>Buffer</code>, this method will throw a\n<code>TypeError</code>. If <code>value</code> is a number, it will be coerced to a valid byte value,\nan integer between 0 and 255.</p>\n<p>If <code>byteOffset</code> is not a number, it will be coerced to a number. Any arguments\nthat coerce to <code>NaN</code> or 0, like <code>{}</code>, <code>[]</code>, <code>null</code> or <code>undefined</code>, will search\nthe whole buffer. This behavior matches <a href=\"https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/indexOf\"><code>String#indexOf()</code></a>.</p>\n<pre><code class=\"lang-js\">const 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', []));\n</code></pre>\n<p>If <code>value</code> is an empty string or empty <code>Buffer</code> and <code>byteOffset</code> is less\nthan <code>buf.length</code>, <code>byteOffset</code> will be returned. If <code>value</code> is empty and\n<code>byteOffset</code> is at least <code>buf.length</code>, <code>buf.length</code> will be returned.</p>\n"
},
{
"textRaw": "buf.keys()",
"type": "method",
"name": "keys",
"meta": {
"added": [
"v1.1.0"
],
"changes": []
},
"signatures": [
{
"return": {
"textRaw": "Returns: {Iterator} ",
"name": "return",
"type": "Iterator"
},
"params": []
},
{
"params": []
}
],
"desc": "<p>Creates and returns an <a href=\"https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Iteration_protocols\">iterator</a> of <code>buf</code> keys (indices).</p>\n<pre><code class=\"lang-js\">const 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\n</code></pre>\n"
},
{
"textRaw": "buf.lastIndexOf(value[, byteOffset][, encoding])",
"type": "method",
"name": "lastIndexOf",
"meta": {
"added": [
"v6.0.0"
],
"changes": [
{
"version": "v8.0.0",
"pr-url": "https://github.com/nodejs/node/pull/10236",
"description": "The `value` can now be a `Uint8Array`."
}
]
},
"signatures": [
{
"return": {
"textRaw": "Returns: {integer} The index of the last occurrence of `value` in `buf` or `-1` if `buf` does not contain `value`. ",
"name": "return",
"type": "integer",
"desc": "The index of the last occurrence of `value` in `buf` or `-1` if `buf` does not contain `value`."
},
"params": [
{
"textRaw": "`value` {string|Buffer|Uint8Array|integer} What to search for. ",
"name": "value",
"type": "string|Buffer|Uint8Array|integer",
"desc": "What to search for."
},
{
"textRaw": "`byteOffset` {integer} Where to begin searching in `buf`. **Default:** [`buf.length`]` - 1` ",
"name": "byteOffset",
"type": "integer",
"desc": "Where to begin searching in `buf`. **Default:** [`buf.length`]` - 1`",
"optional": true
},
{
"textRaw": "`encoding` {string} If `value` is a string, this is its encoding. **Default:** `'utf8'` ",
"name": "encoding",
"type": "string",
"desc": "If `value` is a string, this is its encoding. **Default:** `'utf8'`",
"optional": true
}
]
},
{
"params": [
{
"name": "value"
},
{
"name": "byteOffset",
"optional": true
},
{
"name": "encoding",
"optional": true
}
]
}
],
"desc": "<p>Identical to <a href=\"#buffer_buf_indexof_value_byteoffset_encoding\"><code>buf.indexOf()</code></a>, except <code>buf</code> is searched from back to front\ninstead of front to back.</p>\n<pre><code class=\"lang-js\">const 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\n</code></pre>\n<p>If <code>value</code> is not a string, number, or <code>Buffer</code>, this method will throw a\n<code>TypeError</code>. If <code>value</code> is a number, it will be coerced to a valid byte value,\nan integer between 0 and 255.</p>\n<p>If <code>byteOffset</code> is not a number, it will be coerced to a number. Any arguments\nthat coerce to <code>NaN</code>, like <code>{}</code> or <code>undefined</code>, will search the whole buffer.\nThis behavior matches <a href=\"https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/lastIndexOf\"><code>String#lastIndexOf()</code></a>.</p>\n<pre><code class=\"lang-js\">const 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', []));\n</code></pre>\n<p>If <code>value</code> is an empty string or empty <code>Buffer</code>, <code>byteOffset</code> will be returned.</p>\n"
},
{
"textRaw": "buf.readDoubleBE(offset[, noAssert])",
"type": "method",
"name": "readDoubleBE",
"meta": {
"added": [
"v0.11.15"
],
"changes": []
},
"signatures": [
{
"return": {
"textRaw": "Returns: {number} ",
"name": "return",
"type": "number"
},
"params": [
{
"textRaw": "`offset` {integer} Number of bytes to skip before starting to read. Must satisfy: `0 <= offset <= buf.length - 8`. ",
"name": "offset",
"type": "integer",
"desc": "Number of bytes to skip before starting to read. Must satisfy: `0 <= offset <= buf.length - 8`."
},
{
"textRaw": "`noAssert` {boolean} Skip `offset` validation? **Default:** `false` ",
"name": "noAssert",
"type": "boolean",
"desc": "Skip `offset` validation? **Default:** `false`",
"optional": true
}
]
},
{
"params": [
{
"name": "offset"
},
{
"name": "noAssert",
"optional": true
}
]
},
{
"params": [
{
"name": "offset"
},
{
"name": "noAssert",
"optional": true
}
]
}
],
"desc": "<p>Reads a 64-bit double from <code>buf</code> at the specified <code>offset</code> with specified\nendian format (<code>readDoubleBE()</code> returns big endian, <code>readDoubleLE()</code> returns\nlittle endian).</p>\n<p>Setting <code>noAssert</code> to <code>true</code> allows <code>offset</code> to be beyond the end of <code>buf</code>, but\nthe resulting behavior is undefined.</p>\n<pre><code class=\"lang-js\">const buf = Buffer.from([1, 2, 3, 4, 5, 6, 7, 8]);\n\nconsole.log(buf.readDoubleBE());\n// Prints: 8.20788039913184e-304\nconsole.log(buf.readDoubleLE());\n// Prints: 5.447603722011605e-270\nconsole.log(buf.readDoubleLE(1));\n// Throws an exception: RangeError: Index out of range\nconsole.log(buf.readDoubleLE(1, true));\n// Warning: reads passed end of buffer!\n// This will result in a segmentation fault! Don't do this!\n</code></pre>\n"
},
{
"textRaw": "buf.readDoubleLE(offset[, noAssert])",
"type": "method",
"name": "readDoubleLE",
"meta": {
"added": [
"v0.11.15"
],
"changes": []
},
"signatures": [
{
"return": {
"textRaw": "Returns: {number} ",
"name": "return",
"type": "number"
},
"params": [
{
"textRaw": "`offset` {integer} Number of bytes to skip before starting to read. Must satisfy: `0 <= offset <= buf.length - 8`. ",
"name": "offset",
"type": "integer",
"desc": "Number of bytes to skip before starting to read. Must satisfy: `0 <= offset <= buf.length - 8`."
},
{
"textRaw": "`noAssert` {boolean} Skip `offset` validation? **Default:** `false` ",
"name": "noAssert",
"type": "boolean",
"desc": "Skip `offset` validation? **Default:** `false`",
"optional": true
}
]
},
{
"params": [
{
"name": "offset"
},
{
"name": "noAssert",
"optional": true
}
]
}
],
"desc": "<p>Reads a 64-bit double from <code>buf</code> at the specified <code>offset</code> with specified\nendian format (<code>readDoubleBE()</code> returns big endian, <code>readDoubleLE()</code> returns\nlittle endian).</p>\n<p>Setting <code>noAssert</code> to <code>true</code> allows <code>offset</code> to be beyond the end of <code>buf</code>, but\nthe resulting behavior is undefined.</p>\n<pre><code class=\"lang-js\">const buf = Buffer.from([1, 2, 3, 4, 5, 6, 7, 8]);\n\nconsole.log(buf.readDoubleBE());\n// Prints: 8.20788039913184e-304\nconsole.log(buf.readDoubleLE());\n// Prints: 5.447603722011605e-270\nconsole.log(buf.readDoubleLE(1));\n// Throws an exception: RangeError: Index out of range\nconsole.log(buf.readDoubleLE(1, true));\n// Warning: reads passed end of buffer!\n// This will result in a segmentation fault! Don't do this!\n</code></pre>\n"
},
{
"textRaw": "buf.readFloatBE(offset[, noAssert])",
"type": "method",
"name": "readFloatBE",
"meta": {
"added": [
"v0.11.15"
],
"changes": []
},
"signatures": [
{
"return": {
"textRaw": "Returns: {number} ",
"name": "return",
"type": "number"
},
"params": [
{
"textRaw": "`offset` {integer} Number of bytes to skip before starting to read. Must satisfy: `0 <= offset <= buf.length - 4`. ",
"name": "offset",
"type": "integer",
"desc": "Number of bytes to skip before starting to read. Must satisfy: `0 <= offset <= buf.length - 4`."
},
{
"textRaw": "`noAssert` {boolean} Skip `offset` validation? **Default:** `false` ",
"name": "noAssert",
"type": "boolean",
"desc": "Skip `offset` validation? **Default:** `false`",
"optional": true
}
]
},
{
"params": [
{
"name": "offset"
},
{
"name": "noAssert",
"optional": true
}
]
},
{
"params": [
{
"name": "offset"
},
{
"name": "noAssert",
"optional": true
}
]
}
],
"desc": "<p>Reads a 32-bit float from <code>buf</code> at the specified <code>offset</code> with specified\nendian format (<code>readFloatBE()</code> returns big endian, <code>readFloatLE()</code> returns\nlittle endian).</p>\n<p>Setting <code>noAssert</code> to <code>true</code> allows <code>offset</code> to be beyond the end of <code>buf</code>, but\nthe resulting behavior is undefined.</p>\n<pre><code class=\"lang-js\">const buf = Buffer.from([1, 2, 3, 4]);\n\nconsole.log(buf.readFloatBE());\n// Prints: 2.387939260590663e-38\nconsole.log(buf.readFloatLE());\n// Prints: 1.539989614439558e-36\nconsole.log(buf.readFloatLE(1));\n// Throws an exception: RangeError: Index out of range\nconsole.log(buf.readFloatLE(1, true));\n// Warning: reads passed end of buffer!\n// This will result in a segmentation fault! Don't do this!\n</code></pre>\n"
},
{
"textRaw": "buf.readFloatLE(offset[, noAssert])",
"type": "method",
"name": "readFloatLE",
"meta": {
"added": [
"v0.11.15"
],
"changes": []
},
"signatures": [
{
"return": {
"textRaw": "Returns: {number} ",
"name": "return",
"type": "number"
},
"params": [
{
"textRaw": "`offset` {integer} Number of bytes to skip before starting to read. Must satisfy: `0 <= offset <= buf.length - 4`. ",
"name": "offset",
"type": "integer",
"desc": "Number of bytes to skip before starting to read. Must satisfy: `0 <= offset <= buf.length - 4`."
},
{
"textRaw": "`noAssert` {boolean} Skip `offset` validation? **Default:** `false` ",
"name": "noAssert",
"type": "boolean",
"desc": "Skip `offset` validation? **Default:** `false`",
"optional": true
}
]
},
{
"params": [
{
"name": "offset"
},
{
"name": "noAssert",
"optional": true
}
]
}
],
"desc": "<p>Reads a 32-bit float from <code>buf</code> at the specified <code>offset</code> with specified\nendian format (<code>readFloatBE()</code> returns big endian, <code>readFloatLE()</code> returns\nlittle endian).</p>\n<p>Setting <code>noAssert</code> to <code>true</code> allows <code>offset</code> to be beyond the end of <code>buf</code>, but\nthe resulting behavior is undefined.</p>\n<pre><code class=\"lang-js\">const buf = Buffer.from([1, 2, 3, 4]);\n\nconsole.log(buf.readFloatBE());\n// Prints: 2.387939260590663e-38\nconsole.log(buf.readFloatLE());\n// Prints: 1.539989614439558e-36\nconsole.log(buf.readFloatLE(1));\n// Throws an exception: RangeError: Index out of range\nconsole.log(buf.readFloatLE(1, true));\n// Warning: reads passed end of buffer!\n// This will result in a segmentation fault! Don't do this!\n</code></pre>\n"
},
{
"textRaw": "buf.readInt8(offset[, noAssert])",
"type": "method",
"name": "readInt8",
"meta": {
"added": [
"v0.5.0"
],
"changes": []
},
"signatures": [
{
"return": {
"textRaw": "Returns: {integer} ",
"name": "return",
"type": "integer"
},
"params": [
{
"textRaw": "`offset` {integer} Number of bytes to skip before starting to read. Must satisfy: `0 <= offset <= buf.length - 1`. ",
"name": "offset",
"type": "integer",
"desc": "Number of bytes to skip before starting to read. Must satisfy: `0 <= offset <= buf.length - 1`."
},
{
"textRaw": "`noAssert` {boolean} Skip `offset` validation? **Default:** `false` ",
"name": "noAssert",
"type": "boolean",
"desc": "Skip `offset` validation? **Default:** `false`",
"optional": true
}
]
},
{
"params": [
{
"name": "offset"
},
{
"name": "noAssert",
"optional": true
}
]
}
],
"desc": "<p>Reads a signed 8-bit integer from <code>buf</code> at the specified <code>offset</code>.</p>\n<p>Setting <code>noAssert</code> to <code>true</code> allows <code>offset</code> to be beyond the end of <code>buf</code>, but\nthe resulting behavior is undefined.</p>\n<p>Integers read from a <code>Buffer</code> are interpreted as two's complement signed values.</p>\n<pre><code class=\"lang-js\">const 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 an exception: RangeError: Index out of range\n</code></pre>\n"
},
{
"textRaw": "buf.readInt16BE(offset[, noAssert])",
"type": "method",
"name": "readInt16BE",
"meta": {
"added": [
"v0.5.5"
],
"changes": []
},
"signatures": [
{
"return": {
"textRaw": "Returns: {integer} ",
"name": "return",
"type": "integer"
},
"params": [
{
"textRaw": "`offset` {integer} Number of bytes to skip before starting to read. Must satisfy: `0 <= offset <= buf.length - 2`. ",
"name": "offset",
"type": "integer",
"desc": "Number of bytes to skip before starting to read. Must satisfy: `0 <= offset <= buf.length - 2`."
},
{
"textRaw": "`noAssert` {boolean} Skip `offset` validation? **Default:** `false` ",
"name": "noAssert",
"type": "boolean",
"desc": "Skip `offset` validation? **Default:** `false`",
"optional": true
}
]
},
{
"params": [
{
"name": "offset"
},
{
"name": "noAssert",
"optional": true
}
]
},
{
"params": [
{
"name": "offset"
},
{
"name": "noAssert",
"optional": true
}
]
}
],
"desc": "<p>Reads a signed 16-bit integer from <code>buf</code> at the specified <code>offset</code> with\nthe specified endian format (<code>readInt16BE()</code> returns big endian,\n<code>readInt16LE()</code> returns little endian).</p>\n<p>Setting <code>noAssert</code> to <code>true</code> allows <code>offset</code> to be beyond the end of <code>buf</code>, but\nthe resulting behavior is undefined.</p>\n<p>Integers read from a <code>Buffer</code> are interpreted as two's complement signed values.</p>\n<pre><code class=\"lang-js\">const buf = Buffer.from([0, 5]);\n\nconsole.log(buf.readInt16BE());\n// Prints: 5\nconsole.log(buf.readInt16LE());\n// Prints: 1280\nconsole.log(buf.readInt16LE(1));\n// Throws an exception: RangeError: Index out of range\n</code></pre>\n"
},
{
"textRaw": "buf.readInt16LE(offset[, noAssert])",
"type": "method",
"name": "readInt16LE",
"meta": {
"added": [
"v0.5.5"
],
"changes": []
},
"signatures": [
{
"return": {
"textRaw": "Returns: {integer} ",
"name": "return",
"type": "integer"
},
"params": [
{
"textRaw": "`offset` {integer} Number of bytes to skip before starting to read. Must satisfy: `0 <= offset <= buf.length - 2`. ",
"name": "offset",
"type": "integer",
"desc": "Number of bytes to skip before starting to read. Must satisfy: `0 <= offset <= buf.length - 2`."
},
{
"textRaw": "`noAssert` {boolean} Skip `offset` validation? **Default:** `false` ",
"name": "noAssert",
"type": "boolean",
"desc": "Skip `offset` validation? **Default:** `false`",
"optional": true
}
]
},
{
"params": [
{
"name": "offset"
},
{
"name": "noAssert",
"optional": true
}
]
}
],
"desc": "<p>Reads a signed 16-bit integer from <code>buf</code> at the specified <code>offset</code> with\nthe specified endian format (<code>readInt16BE()</code> returns big endian,\n<code>readInt16LE()</code> returns little endian).</p>\n<p>Setting <code>noAssert</code> to <code>true</code> allows <code>offset</code> to be beyond the end of <code>buf</code>, but\nthe resulting behavior is undefined.</p>\n<p>Integers read from a <code>Buffer</code> are interpreted as two's complement signed values.</p>\n<pre><code class=\"lang-js\">const buf = Buffer.from([0, 5]);\n\nconsole.log(buf.readInt16BE());\n// Prints: 5\nconsole.log(buf.readInt16LE());\n// Prints: 1280\nconsole.log(buf.readInt16LE(1));\n// Throws an exception: RangeError: Index out of range\n</code></pre>\n"
},
{
"textRaw": "buf.readInt32BE(offset[, noAssert])",
"type": "method",
"name": "readInt32BE",
"meta": {
"added": [
"v0.5.5"
],
"changes": []
},
"signatures": [
{
"return": {
"textRaw": "Returns: {integer} ",
"name": "return",
"type": "integer"
},
"params": [
{
"textRaw": "`offset` {integer} Number of bytes to skip before starting to read. Must satisfy: `0 <= offset <= buf.length - 4`. ",
"name": "offset",
"type": "integer",
"desc": "Number of bytes to skip before starting to read. Must satisfy: `0 <= offset <= buf.length - 4`."
},
{
"textRaw": "`noAssert` {boolean} Skip `offset` validation? **Default:** `false` ",
"name": "noAssert",
"type": "boolean",
"desc": "Skip `offset` validation? **Default:** `false`",
"optional": true
}
]
},
{
"params": [
{
"name": "offset"
},
{
"name": "noAssert",
"optional": true
}
]
},
{
"params": [
{
"name": "offset"
},
{
"name": "noAssert",
"optional": true
}
]
}
],
"desc": "<p>Reads a signed 32-bit integer from <code>buf</code> at the specified <code>offset</code> with\nthe specified endian format (<code>readInt32BE()</code> returns big endian,\n<code>readInt32LE()</code> returns little endian).</p>\n<p>Setting <code>noAssert</code> to <code>true</code> allows <code>offset</code> to be beyond the end of <code>buf</code>, but\nthe resulting behavior is undefined.</p>\n<p>Integers read from a <code>Buffer</code> are interpreted as two's complement signed values.</p>\n<pre><code class=\"lang-js\">const buf = Buffer.from([0, 0, 0, 5]);\n\nconsole.log(buf.readInt32BE());\n// Prints: 5\nconsole.log(buf.readInt32LE());\n// Prints: 83886080\nconsole.log(buf.readInt32LE(1));\n// Throws an exception: RangeError: Index out of range\n</code></pre>\n"
},
{
"textRaw": "buf.readInt32LE(offset[, noAssert])",
"type": "method",
"name": "readInt32LE",
"meta": {
"added": [
"v0.5.5"
],
"changes": []
},
"signatures": [
{
"return": {
"textRaw": "Returns: {integer} ",
"name": "return",
"type": "integer"
},
"params": [
{
"textRaw": "`offset` {integer} Number of bytes to skip before starting to read. Must satisfy: `0 <= offset <= buf.length - 4`. ",
"name": "offset",
"type": "integer",
"desc": "Number of bytes to skip before starting to read. Must satisfy: `0 <= offset <= buf.length - 4`."
},
{
"textRaw": "`noAssert` {boolean} Skip `offset` validation? **Default:** `false` ",
"name": "noAssert",
"type": "boolean",
"desc": "Skip `offset` validation? **Default:** `false`",
"optional": true
}
]
},
{
"params": [
{
"name": "offset"
},
{
"name": "noAssert",
"optional": true
}
]
}
],
"desc": "<p>Reads a signed 32-bit integer from <code>buf</code> at the specified <code>offset</code> with\nthe specified endian format (<code>readInt32BE()</code> returns big endian,\n<code>readInt32LE()</code> returns little endian).</p>\n<p>Setting <code>noAssert</code> to <code>true</code> allows <code>offset</code> to be beyond the end of <code>buf</code>, but\nthe resulting behavior is undefined.</p>\n<p>Integers read from a <code>Buffer</code> are interpreted as two's complement signed values.</p>\n<pre><code class=\"lang-js\">const buf = Buffer.from([0, 0, 0, 5]);\n\nconsole.log(buf.readInt32BE());\n// Prints: 5\nconsole.log(buf.readInt32LE());\n// Prints: 83886080\nconsole.log(buf.readInt32LE(1));\n// Throws an exception: RangeError: Index out of range\n</code></pre>\n"
},
{
"textRaw": "buf.readIntBE(offset, byteLength[, noAssert])",
"type": "method",
"name": "readIntBE",
"meta": {
"added": [
"v0.11.15"
],
"changes": []
},
"signatures": [
{
"return": {
"textRaw": "Returns: {integer} ",
"name": "return",
"type": "integer"
},
"params": [
{
"textRaw": "`offset` {integer} Number of bytes to skip before starting to read. Must satisfy: `0 <= offset <= buf.length - byteLength`. ",
"name": "offset",
"type": "integer",
"desc": "Number of bytes to skip before starting to read. Must satisfy: `0 <= offset <= buf.length - byteLength`."
},
{
"textRaw": "`byteLength` {integer} Number of bytes to read. Must satisfy: `0 < byteLength <= 6`. ",
"name": "byteLength",
"type": "integer",
"desc": "Number of bytes to read. Must satisfy: `0 < byteLength <= 6`."
},
{
"textRaw": "`noAssert` {boolean} Skip `offset` and `byteLength` validation? **Default:** `false`. ",
"name": "noAssert",
"type": "boolean",
"desc": "Skip `offset` and `byteLength` validation? **Default:** `false`.",
"optional": true
}
]
},
{
"params": [
{
"name": "offset"
},
{
"name": "byteLength"
},
{
"name": "noAssert",
"optional": true
}
]
},
{
"params": [
{
"name": "offset"
},
{
"name": "byteLength"
},
{
"name": "noAssert",
"optional": true
}
]
}
],
"desc": "<p>Reads <code>byteLength</code> number of bytes from <code>buf</code> at the specified <code>offset</code>\nand interprets the result as a two's complement signed value. Supports up to 48\nbits of accuracy.</p>\n<p>Setting <code>noAssert</code> to <code>true</code> allows <code>offset</code> to be beyond the end of <code>buf</code>, but\nthe resulting behavior is undefined.</p>\n<pre><code class=\"lang-js\">const buf = Buffer.from([0x12, 0x34, 0x56, 0x78, 0x90, 0xab]);\n\nconsole.log(buf.readIntLE(0, 6).toString(16));\n// Prints: -546f87a9cbee\nconsole.log(buf.readIntBE(0, 6).toString(16));\n// Prints: 1234567890ab\nconsole.log(buf.readIntBE(1, 6).toString(16));\n// Throws: RangeError [ERR_INDEX_OUT_OF_RANGE]: Index out of range\n</code></pre>\n"
},
{
"textRaw": "buf.readIntLE(offset, byteLength[, noAssert])",
"type": "method",
"name": "readIntLE",
"meta": {
"added": [
"v0.11.15"
],
"changes": []
},
"signatures": [
{
"return": {
"textRaw": "Returns: {integer} ",
"name": "return",
"type": "integer"
},
"params": [
{
"textRaw": "`offset` {integer} Number of bytes to skip before starting to read. Must satisfy: `0 <= offset <= buf.length - byteLength`. ",
"name": "offset",
"type": "integer",
"desc": "Number of bytes to skip before starting to read. Must satisfy: `0 <= offset <= buf.length - byteLength`."
},
{
"textRaw": "`byteLength` {integer} Number of bytes to read. Must satisfy: `0 < byteLength <= 6`. ",
"name": "byteLength",
"type": "integer",
"desc": "Number of bytes to read. Must satisfy: `0 < byteLength <= 6`."
},
{
"textRaw": "`noAssert` {boolean} Skip `offset` and `byteLength` validation? **Default:** `false`. ",
"name": "noAssert",
"type": "boolean",
"desc": "Skip `offset` and `byteLength` validation? **Default:** `false`.",
"optional": true
}
]
},
{
"params": [
{
"name": "offset"
},
{
"name": "byteLength"
},
{
"name": "noAssert",
"optional": true
}
]
}
],
"desc": "<p>Reads <code>byteLength</code> number of bytes from <code>buf</code> at the specified <code>offset</code>\nand interprets the result as a two's complement signed value. Supports up to 48\nbits of accuracy.</p>\n<p>Setting <code>noAssert</code> to <code>true</code> allows <code>offset</code> to be beyond the end of <code>buf</code>, but\nthe resulting behavior is undefined.</p>\n<pre><code class=\"lang-js\">const buf = Buffer.from([0x12, 0x34, 0x56, 0x78, 0x90, 0xab]);\n\nconsole.log(buf.readIntLE(0, 6).toString(16));\n// Prints: -546f87a9cbee\nconsole.log(buf.readIntBE(0, 6).toString(16));\n// Prints: 1234567890ab\nconsole.log(buf.readIntBE(1, 6).toString(16));\n// Throws: RangeError [ERR_INDEX_OUT_OF_RANGE]: Index out of range\n</code></pre>\n"
},
{
"textRaw": "buf.readUInt8(offset[, noAssert])",
"type": "method",
"name": "readUInt8",
"meta": {
"added": [
"v0.5.0"
],
"changes": []
},
"signatures": [
{
"return": {
"textRaw": "Returns: {integer} ",
"name": "return",
"type": "integer"
},
"params": [
{
"textRaw": "`offset` {integer} Number of bytes to skip before starting to read. Must satisfy: `0 <= offset <= buf.length - 1`. ",
"name": "offset",
"type": "integer",
"desc": "Number of bytes to skip before starting to read. Must satisfy: `0 <= offset <= buf.length - 1`."
},
{
"textRaw": "`noAssert` {boolean} Skip `offset` validation? **Default:** `false` ",
"name": "noAssert",
"type": "boolean",
"desc": "Skip `offset` validation? **Default:** `false`",
"optional": true
}
]
},
{
"params": [
{
"name": "offset"
},
{
"name": "noAssert",
"optional": true
}
]
}
],
"desc": "<p>Reads an unsigned 8-bit integer from <code>buf</code> at the specified <code>offset</code>.</p>\n<p>Setting <code>noAssert</code> to <code>true</code> allows <code>offset</code> to be beyond the end of <code>buf</code>, but\nthe resulting behavior is undefined.</p>\n<pre><code class=\"lang-js\">const 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 an exception: RangeError: Index out of range\n</code></pre>\n"
},
{
"textRaw": "buf.readUInt16BE(offset[, noAssert])",
"type": "method",
"name": "readUInt16BE",
"meta": {
"added": [
"v0.5.5"
],
"changes": []
},
"signatures": [
{
"return": {
"textRaw": "Returns: {integer} ",
"name": "return",
"type": "integer"
},
"params": [
{
"textRaw": "`offset` {integer} Number of bytes to skip before starting to read. Must satisfy: `0 <= offset <= buf.length - 2`. ",
"name": "offset",
"type": "integer",
"desc": "Number of bytes to skip before starting to read. Must satisfy: `0 <= offset <= buf.length - 2`."
},
{
"textRaw": "`noAssert` {boolean} Skip `offset` validation? **Default:** `false` ",
"name": "noAssert",
"type": "boolean",
"desc": "Skip `offset` validation? **Default:** `false`",
"optional": true
}
]
},
{
"params": [
{
"name": "offset"
},
{
"name": "noAssert",
"optional": true
}
]
},
{
"params": [
{
"name": "offset"
},
{
"name": "noAssert",
"optional": true
}
]
}
],
"desc": "<p>Reads an unsigned 16-bit integer from <code>buf</code> at the specified <code>offset</code> with\nspecified endian format (<code>readUInt16BE()</code> returns big endian, <code>readUInt16LE()</code>\nreturns little endian).</p>\n<p>Setting <code>noAssert</code> to <code>true</code> allows <code>offset</code> to be beyond the end of <code>buf</code>, but\nthe resulting behavior is undefined.</p>\n<pre><code class=\"lang-js\">const buf = Buffer.from([0x12, 0x34, 0x56]);\n\nconsole.log(buf.readUInt16BE(0).toString(16));\n// Prints: 1234\nconsole.log(buf.readUInt16LE(0).toString(16));\n// Prints: 3412\nconsole.log(buf.readUInt16BE(1).toString(16));\n// Prints: 3456\nconsole.log(buf.readUInt16LE(1).toString(16));\n// Prints: 5634\nconsole.log(buf.readUInt16LE(2).toString(16));\n// Throws an exception: RangeError: Index out of range\n</code></pre>\n"
},
{
"textRaw": "buf.readUInt16LE(offset[, noAssert])",
"type": "method",
"name": "readUInt16LE",
"meta": {
"added": [
"v0.5.5"
],
"changes": []
},
"signatures": [
{
"return": {
"textRaw": "Returns: {integer} ",
"name": "return",
"type": "integer"
},
"params": [
{
"textRaw": "`offset` {integer} Number of bytes to skip before starting to read. Must satisfy: `0 <= offset <= buf.length - 2`. ",
"name": "offset",
"type": "integer",
"desc": "Number of bytes to skip before starting to read. Must satisfy: `0 <= offset <= buf.length - 2`."
},
{
"textRaw": "`noAssert` {boolean} Skip `offset` validation? **Default:** `false` ",
"name": "noAssert",
"type": "boolean",
"desc": "Skip `offset` validation? **Default:** `false`",
"optional": true
}
]
},
{
"params": [
{
"name": "offset"
},
{
"name": "noAssert",
"optional": true
}
]
}
],
"desc": "<p>Reads an unsigned 16-bit integer from <code>buf</code> at the specified <code>offset</code> with\nspecified endian format (<code>readUInt16BE()</code> returns big endian, <code>readUInt16LE()</code>\nreturns little endian).</p>\n<p>Setting <code>noAssert</code> to <code>true</code> allows <code>offset</code> to be beyond the end of <code>buf</code>, but\nthe resulting behavior is undefined.</p>\n<pre><code class=\"lang-js\">const buf = Buffer.from([0x12, 0x34, 0x56]);\n\nconsole.log(buf.readUInt16BE(0).toString(16));\n// Prints: 1234\nconsole.log(buf.readUInt16LE(0).toString(16));\n// Prints: 3412\nconsole.log(buf.readUInt16BE(1).toString(16));\n// Prints: 3456\nconsole.log(buf.readUInt16LE(1).toString(16));\n// Prints: 5634\nconsole.log(buf.readUInt16LE(2).toString(16));\n// Throws an exception: RangeError: Index out of range\n</code></pre>\n"
},
{
"textRaw": "buf.readUInt32BE(offset[, noAssert])",
"type": "method",
"name": "readUInt32BE",
"meta": {
"added": [
"v0.5.5"
],
"changes": []
},
"signatures": [
{
"return": {
"textRaw": "Returns: {integer} ",
"name": "return",
"type": "integer"
},
"params": [
{
"textRaw": "`offset` {integer} Number of bytes to skip before starting to read. Must satisfy: `0 <= offset <= buf.length - 4`. ",
"name": "offset",
"type": "integer",
"desc": "Number of bytes to skip before starting to read. Must satisfy: `0 <= offset <= buf.length - 4`."
},
{
"textRaw": "`noAssert` {boolean} Skip `offset` validation? **Default:** `false` ",
"name": "noAssert",
"type": "boolean",
"desc": "Skip `offset` validation? **Default:** `false`",
"optional": true
}
]
},
{
"params": [
{
"name": "offset"
},
{
"name": "noAssert",
"optional": true
}
]
},
{
"params": [
{
"name": "offset"
},
{
"name": "noAssert",
"optional": true
}
]
}
],
"desc": "<p>Reads an unsigned 32-bit integer from <code>buf</code> at the specified <code>offset</code> with\nspecified endian format (<code>readUInt32BE()</code> returns big endian,\n<code>readUInt32LE()</code> returns little endian).</p>\n<p>Setting <code>noAssert</code> to <code>true</code> allows <code>offset</code> to be beyond the end of <code>buf</code>, but\nthe resulting behavior is undefined.</p>\n<pre><code class=\"lang-js\">const buf = Buffer.from([0x12, 0x34, 0x56, 0x78]);\n\nconsole.log(buf.readUInt32BE(0).toString(16));\n// Prints: 12345678\nconsole.log(buf.readUInt32LE(0).toString(16));\n// Prints: 78563412\nconsole.log(buf.readUInt32LE(1).toString(16));\n// Throws an exception: RangeError: Index out of range\n</code></pre>\n"
},
{
"textRaw": "buf.readUInt32LE(offset[, noAssert])",
"type": "method",
"name": "readUInt32LE",
"meta": {
"added": [
"v0.5.5"
],
"changes": []
},
"signatures": [
{
"return": {
"textRaw": "Returns: {integer} ",
"name": "return",
"type": "integer"
},
"params": [
{
"textRaw": "`offset` {integer} Number of bytes to skip before starting to read. Must satisfy: `0 <= offset <= buf.length - 4`. ",
"name": "offset",
"type": "integer",
"desc": "Number of bytes to skip before starting to read. Must satisfy: `0 <= offset <= buf.length - 4`."
},
{
"textRaw": "`noAssert` {boolean} Skip `offset` validation? **Default:** `false` ",
"name": "noAssert",
"type": "boolean",
"desc": "Skip `offset` validation? **Default:** `false`",
"optional": true
}
]
},
{
"params": [
{
"name": "offset"
},
{
"name": "noAssert",
"optional": true
}
]
}
],
"desc": "<p>Reads an unsigned 32-bit integer from <code>buf</code> at the specified <code>offset</code> with\nspecified endian format (<code>readUInt32BE()</code> returns big endian,\n<code>readUInt32LE()</code> returns little endian).</p>\n<p>Setting <code>noAssert</code> to <code>true</code> allows <code>offset</code> to be beyond the end of <code>buf</code>, but\nthe resulting behavior is undefined.</p>\n<pre><code class=\"lang-js\">const buf = Buffer.from([0x12, 0x34, 0x56, 0x78]);\n\nconsole.log(buf.readUInt32BE(0).toString(16));\n// Prints: 12345678\nconsole.log(buf.readUInt32LE(0).toString(16));\n// Prints: 78563412\nconsole.log(buf.readUInt32LE(1).toString(16));\n// Throws an exception: RangeError: Index out of range\n</code></pre>\n"
},
{
"textRaw": "buf.readUIntBE(offset, byteLength[, noAssert])",
"type": "method",
"name": "readUIntBE",
"meta": {
"added": [
"v0.11.15"
],
"changes": []
},
"signatures": [
{
"return": {
"textRaw": "Returns: {integer} ",
"name": "return",
"type": "integer"
},
"params": [
{
"textRaw": "`offset` {integer} Number of bytes to skip before starting to read. Must satisfy: `0 <= offset <= buf.length - byteLength`. ",
"name": "offset",
"type": "integer",
"desc": "Number of bytes to skip before starting to read. Must satisfy: `0 <= offset <= buf.length - byteLength`."
},
{
"textRaw": "`byteLength` {integer} Number of bytes to read. Must satisfy: `0 < byteLength <= 6`. ",
"name": "byteLength",
"type": "integer",
"desc": "Number of bytes to read. Must satisfy: `0 < byteLength <= 6`."
},
{
"textRaw": "`noAssert` {boolean} Skip `offset` and `byteLength` validation? **Default:** `false` ",
"name": "noAssert",
"type": "boolean",
"desc": "Skip `offset` and `byteLength` validation? **Default:** `false`",
"optional": true
}
]
},
{
"params": [
{
"name": "offset"
},
{
"name": "byteLength"
},
{
"name": "noAssert",
"optional": true
}
]
},
{
"params": [
{
"name": "offset"
},
{
"name": "byteLength"
},
{
"name": "noAssert",
"optional": true
}
]
}
],
"desc": "<p>Reads <code>byteLength</code> number of bytes from <code>buf</code> at the specified <code>offset</code>\nand interprets the result as an unsigned integer. Supports up to 48\nbits of accuracy.</p>\n<p>Setting <code>noAssert</code> to <code>true</code> allows <code>offset</code> to be beyond the end of <code>buf</code>, but\nthe resulting behavior is undefined.</p>\n<pre><code class=\"lang-js\">const buf = Buffer.from([0x12, 0x34, 0x56, 0x78, 0x90, 0xab]);\n\nconsole.log(buf.readUIntBE(0, 6).toString(16));\n// Prints: 1234567890ab\nconsole.log(buf.readUIntLE(0, 6).toString(16));\n// Prints: ab9078563412\nconsole.log(buf.readUIntBE(1, 6).toString(16));\n// Throws an exception: RangeError: Index out of range\n</code></pre>\n"
},
{
"textRaw": "buf.readUIntLE(offset, byteLength[, noAssert])",
"type": "method",
"name": "readUIntLE",
"meta": {
"added": [
"v0.11.15"
],
"changes": []
},
"signatures": [
{
"return": {
"textRaw": "Returns: {integer} ",
"name": "return",
"type": "integer"
},
"params": [
{
"textRaw": "`offset` {integer} Number of bytes to skip before starting to read. Must satisfy: `0 <= offset <= buf.length - byteLength`. ",
"name": "offset",
"type": "integer",
"desc": "Number of bytes to skip before starting to read. Must satisfy: `0 <= offset <= buf.length - byteLength`."
},
{
"textRaw": "`byteLength` {integer} Number of bytes to read. Must satisfy: `0 < byteLength <= 6`. ",
"name": "byteLength",
"type": "integer",
"desc": "Number of bytes to read. Must satisfy: `0 < byteLength <= 6`."
},
{
"textRaw": "`noAssert` {boolean} Skip `offset` and `byteLength` validation? **Default:** `false` ",
"name": "noAssert",
"type": "boolean",
"desc": "Skip `offset` and `byteLength` validation? **Default:** `false`",
"optional": true
}
]
},
{
"params": [
{
"name": "offset"
},
{
"name": "byteLength"
},
{
"name": "noAssert",
"optional": true
}
]
}
],
"desc": "<p>Reads <code>byteLength</code> number of bytes from <code>buf</code> at the specified <code>offset</code>\nand interprets the result as an unsigned integer. Supports up to 48\nbits of accuracy.</p>\n<p>Setting <code>noAssert</code> to <code>true</code> allows <code>offset</code> to be beyond the end of <code>buf</code>, but\nthe resulting behavior is undefined.</p>\n<pre><code class=\"lang-js\">const buf = Buffer.from([0x12, 0x34, 0x56, 0x78, 0x90, 0xab]);\n\nconsole.log(buf.readUIntBE(0, 6).toString(16));\n// Prints: 1234567890ab\nconsole.log(buf.readUIntLE(0, 6).toString(16));\n// Prints: ab9078563412\nconsole.log(buf.readUIntBE(1, 6).toString(16));\n// Throws an exception: RangeError: Index out of range\n</code></pre>\n"
},
{
"textRaw": "buf.slice([start[, end]])",
"type": "method",
"name": "slice",
"meta": {
"added": [
"v0.3.0"
],
"changes": [
{
"version": "v7.1.0, v6.9.2",
"pr-url": "https://github.com/nodejs/node/pull/9341",
"description": "Coercing the offsets to integers now handles values outside the 32-bit integer range properly."
},
{
"version": "v7.0.0",
"pr-url": "https://github.com/nodejs/node/pull/9101",
"description": "All offsets are now coerced to integers before doing any calculations with them."
}
]
},
"signatures": [
{
"return": {
"textRaw": "Returns: {Buffer} ",
"name": "return",
"type": "Buffer"
},
"params": [
{
"textRaw": "`start` {integer} Where the new `Buffer` will start. **Default:** `0` ",
"name": "start",
"type": "integer",
"desc": "Where the new `Buffer` will start. **Default:** `0`",
"optional": true
},
{
"textRaw": "`end` {integer} Where the new `Buffer` will end (not inclusive). **Default:** [`buf.length`] ",
"name": "end",
"type": "integer",
"desc": "Where the new `Buffer` will end (not inclusive). **Default:** [`buf.length`]",
"optional": true
}
]
},
{
"params": [
{
"name": "start",
"optional": true
},
{
"name": "end",
"optional": true
}
]
}
],
"desc": "<p>Returns a new <code>Buffer</code> that references the same memory as the original, but\noffset and cropped by the <code>start</code> and <code>end</code> indices.</p>\n<p>Specifying <code>end</code> greater than <a href=\"#buffer_buf_length\"><code>buf.length</code></a> will return the same result as\nthat of <code>end</code> equal to <a href=\"#buffer_buf_length\"><code>buf.length</code></a>.</p>\n<p>Modifying the new <code>Buffer</code> slice will modify the memory in the original <code>Buffer</code>\nbecause the allocated memory of the two objects overlap.</p>\n<pre><code class=\"lang-js\">// 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.slice(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\n</code></pre>\n<p>Specifying negative indexes causes the slice to be generated relative to the\nend of <code>buf</code> rather than the beginning.</p>\n<pre><code class=\"lang-js\">const buf = Buffer.from('buffer');\n\nconsole.log(buf.slice(-6, -1).toString());\n// Prints: buffe\n// (Equivalent to buf.slice(0, 5))\n\nconsole.log(buf.slice(-6, -2).toString());\n// Prints: buff\n// (Equivalent to buf.slice(0, 4))\n\nconsole.log(buf.slice(-5, -2).toString());\n// Prints: uff\n// (Equivalent to buf.slice(1, 4))\n</code></pre>\n"
},
{
"textRaw": "buf.swap16()",
"type": "method",
"name": "swap16",
"meta": {
"added": [
"v5.10.0"
],
"changes": []
},
"signatures": [
{
"return": {
"textRaw": "Returns: {Buffer} A reference to `buf`. ",
"name": "return",
"type": "Buffer",
"desc": "A reference to `buf`."
},
"params": []
},
{
"params": []
}
],
"desc": "<p>Interprets <code>buf</code> as an array of unsigned 16-bit integers and swaps the byte-order\n<em>in-place</em>. Throws a <code>RangeError</code> if <a href=\"#buffer_buf_length\"><code>buf.length</code></a> is not a multiple of 2.</p>\n<pre><code class=\"lang-js\">const 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 an exception: RangeError: Buffer size must be a multiple of 16-bits\n</code></pre>\n"
},
{
"textRaw": "buf.swap32()",
"type": "method",
"name": "swap32",
"meta": {
"added": [
"v5.10.0"
],
"changes": []
},
"signatures": [
{
"return": {
"textRaw": "Returns: {Buffer} A reference to `buf`. ",
"name": "return",
"type": "Buffer",
"desc": "A reference to `buf`."
},
"params": []
},
{
"params": []
}
],
"desc": "<p>Interprets <code>buf</code> as an array of unsigned 32-bit integers and swaps the byte-order\n<em>in-place</em>. Throws a <code>RangeError</code> if <a href=\"#buffer_buf_length\"><code>buf.length</code></a> is not a multiple of 4.</p>\n<pre><code class=\"lang-js\">const 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 an exception: RangeError: Buffer size must be a multiple of 32-bits\n</code></pre>\n"
},
{
"textRaw": "buf.swap64()",
"type": "method",
"name": "swap64",
"meta": {
"added": [
"v6.3.0"
],
"changes": []
},
"signatures": [
{
"return": {
"textRaw": "Returns: {Buffer} A reference to `buf`. ",
"name": "return",
"type": "Buffer",
"desc": "A reference to `buf`."
},
"params": []
},
{
"params": []
}
],
"desc": "<p>Interprets <code>buf</code> as an array of 64-bit numbers and swaps the byte-order <em>in-place</em>.\nThrows a <code>RangeError</code> if <a href=\"#buffer_buf_length\"><code>buf.length</code></a> is not a multiple of 8.</p>\n<pre><code class=\"lang-js\">const 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 an exception: RangeError: Buffer size must be a multiple of 64-bits\n</code></pre>\n<p>Note that JavaScript cannot encode 64-bit integers. This method is intended\nfor working with 64-bit floats.</p>\n"
},
{
"textRaw": "buf.toJSON()",
"type": "method",
"name": "toJSON",
"meta": {
"added": [
"v0.9.2"
],
"changes": []
},
"signatures": [
{
"return": {
"textRaw": "Returns: {Object} ",
"name": "return",
"type": "Object"
},
"params": []
},
{
"params": []
}
],
"desc": "<p>Returns a JSON representation of <code>buf</code>. <a href=\"https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/stringify\"><code>JSON.stringify()</code></a> implicitly calls\nthis function when stringifying a <code>Buffer</code> instance.</p>\n<pre><code class=\"lang-js\">const 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.data) :\n value;\n});\n\nconsole.log(copy);\n// Prints: <Buffer 01 02 03 04 05>\n</code></pre>\n"
},
{
"textRaw": "buf.toString([encoding[, start[, end]]])",
"type": "method",
"name": "toString",
"meta": {
"added": [
"v0.1.90"
],
"changes": []
},
"signatures": [
{
"return": {
"textRaw": "Returns: {string} ",
"name": "return",
"type": "string"
},
"params": [
{
"textRaw": "`encoding` {string} The character encoding to decode to. **Default:** `'utf8'` ",
"name": "encoding",
"type": "string",
"desc": "The character encoding to decode to. **Default:** `'utf8'`",
"optional": true
},
{
"textRaw": "`start` {integer} The byte offset to start decoding at. **Default:** `0` ",
"name": "start",
"type": "integer",
"desc": "The byte offset to start decoding at. **Default:** `0`",
"optional": true
},
{
"textRaw": "`end` {integer} The byte offset to stop decoding at (not inclusive). **Default:** [`buf.length`] ",
"name": "end",
"type": "integer",
"desc": "The byte offset to stop decoding at (not inclusive). **Default:** [`buf.length`]",
"optional": true
}
]
},
{
"params": [
{
"name": "encoding",
"optional": true
},
{
"name": "start",
"optional": true
},
{
"name": "end",
"optional": true
}
]
}
],
"desc": "<p>Decodes <code>buf</code> to a string according to the specified character encoding in\n<code>encoding</code>. <code>start</code> and <code>end</code> may be passed to decode only a subset of <code>buf</code>.</p>\n<p>The maximum length of a string instance (in UTF-16 code units) is available\nas <a href=\"#buffer_buffer_constants_max_string_length\"><code>buffer.constants.MAX_STRING_LENGTH</code></a>.</p>\n<pre><code class=\"lang-js\">const 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('ascii'));\n// Prints: abcdefghijklmnopqrstuvwxyz\nconsole.log(buf1.toString('ascii', 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\n</code></pre>\n"
},
{
"textRaw": "buf.values()",
"type": "method",
"name": "values",
"meta": {
"added": [
"v1.1.0"
],
"changes": []
},
"signatures": [
{
"return": {
"textRaw": "Returns: {Iterator} ",
"name": "return",
"type": "Iterator"
},
"params": []
},
{
"params": []
}
],
"desc": "<p>Creates and returns an <a href=\"https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Iteration_protocols\">iterator</a> for <code>buf</code> values (bytes). This function is\ncalled automatically when a <code>Buffer</code> is used in a <code>for..of</code> statement.</p>\n<pre><code class=\"lang-js\">const 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\n</code></pre>\n"
},
{
"textRaw": "buf.write(string[, offset[, length]][, encoding])",
"type": "method",
"name": "write",
"meta": {
"added": [
"v0.1.90"
],
"changes": []
},
"signatures": [
{
"return": {
"textRaw": "Returns: {integer} Number of bytes written. ",
"name": "return",
"type": "integer",
"desc": "Number of bytes written."
},
"params": [
{
"textRaw": "`string` {string} String to be written to `buf`. ",
"name": "string",
"type": "string",
"desc": "String to be written to `buf`."
},
{
"textRaw": "`offset` {integer} Number of bytes to skip before starting to write `string`. **Default:** `0` ",
"name": "offset",
"type": "integer",
"desc": "Number of bytes to skip before starting to write `string`. **Default:** `0`",
"optional": true
},
{
"textRaw": "`length` {integer} Number of bytes to write. **Default:** `buf.length - offset` ",
"name": "length",
"type": "integer",
"desc": "Number of bytes to write. **Default:** `buf.length - offset`",
"optional": true
},
{
"textRaw": "`encoding` {string} The character encoding of `string`. **Default:** `'utf8'` ",
"name": "encoding",
"type": "string",
"desc": "The character encoding of `string`. **Default:** `'utf8'`",
"optional": true
}
]
},
{
"params": [
{
"name": "string"
},
{
"name": "offset",
"optional": true
},
{
"name": "length",
"optional": true
},
{
"name": "encoding",
"optional": true
}
]
}
],
"desc": "<p>Writes <code>string</code> to <code>buf</code> at <code>offset</code> according to the character encoding in <code>encoding</code>.\nThe <code>length</code> parameter is the number of bytes to write. If <code>buf</code> did not contain\nenough space to fit the entire string, only a partial amount of <code>string</code> will\nbe written. However, partially encoded characters will not be written.</p>\n<pre><code class=\"lang-js\">const buf = Buffer.allocUnsafe(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</code></pre>\n"
},
{
"textRaw": "buf.writeDoubleBE(value, offset[, noAssert])",
"type": "method",
"name": "writeDoubleBE",
"meta": {
"added": [
"v0.11.15"
],
"changes": []
},
"signatures": [
{
"return": {
"textRaw": "Returns: {integer} `offset` plus the number of bytes written. ",
"name": "return",
"type": "integer",
"desc": "`offset` plus the number of bytes written."
},
"params": [
{
"textRaw": "`value` {number} Number to be written to `buf`. ",
"name": "value",
"type": "number",
"desc": "Number to be written to `buf`."
},
{
"textRaw": "`offset` {integer} Number of bytes to skip before starting to write. Must satisfy: `0 <= offset <= buf.length - 8`. ",
"name": "offset",
"type": "integer",
"desc": "Number of bytes to skip before starting to write. Must satisfy: `0 <= offset <= buf.length - 8`."
},
{
"textRaw": "`noAssert` {boolean} Skip `value` and `offset` validation? **Default:** `false` ",
"name": "noAssert",
"type": "boolean",
"desc": "Skip `value` and `offset` validation? **Default:** `false`",
"optional": true
}
]
},
{
"params": [
{
"name": "value"
},
{
"name": "offset"
},
{
"name": "noAssert",
"optional": true
}
]
},
{
"params": [
{
"name": "value"
},
{
"name": "offset"
},
{
"name": "noAssert",
"optional": true
}
]
}
],
"desc": "<p>Writes <code>value</code> to <code>buf</code> at the specified <code>offset</code> with specified endian\nformat (<code>writeDoubleBE()</code> writes big endian, <code>writeDoubleLE()</code> writes little\nendian). <code>value</code> <em>should</em> be a valid 64-bit double. Behavior is undefined when\n<code>value</code> is anything other than a 64-bit double.</p>\n<p>Setting <code>noAssert</code> to <code>true</code> allows the encoded form of <code>value</code> to extend beyond\nthe end of <code>buf</code>, but the resulting behavior is undefined.</p>\n<pre><code class=\"lang-js\">const buf = Buffer.allocUnsafe(8);\n\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>\n</code></pre>\n"
},
{
"textRaw": "buf.writeDoubleLE(value, offset[, noAssert])",
"type": "method",
"name": "writeDoubleLE",
"meta": {
"added": [
"v0.11.15"
],
"changes": []
},
"signatures": [
{
"return": {
"textRaw": "Returns: {integer} `offset` plus the number of bytes written. ",
"name": "return",
"type": "integer",
"desc": "`offset` plus the number of bytes written."
},
"params": [
{
"textRaw": "`value` {number} Number to be written to `buf`. ",
"name": "value",
"type": "number",
"desc": "Number to be written to `buf`."
},
{
"textRaw": "`offset` {integer} Number of bytes to skip before starting to write. Must satisfy: `0 <= offset <= buf.length - 8`. ",
"name": "offset",
"type": "integer",
"desc": "Number of bytes to skip before starting to write. Must satisfy: `0 <= offset <= buf.length - 8`."
},
{
"textRaw": "`noAssert` {boolean} Skip `value` and `offset` validation? **Default:** `false` ",
"name": "noAssert",
"type": "boolean",
"desc": "Skip `value` and `offset` validation? **Default:** `false`",
"optional": true
}
]
},
{
"params": [
{
"name": "value"
},
{
"name": "offset"
},
{
"name": "noAssert",
"optional": true
}
]
}
],
"desc": "<p>Writes <code>value</code> to <code>buf</code> at the specified <code>offset</code> with specified endian\nformat (<code>writeDoubleBE()</code> writes big endian, <code>writeDoubleLE()</code> writes little\nendian). <code>value</code> <em>should</em> be a valid 64-bit double. Behavior is undefined when\n<code>value</code> is anything other than a 64-bit double.</p>\n<p>Setting <code>noAssert</code> to <code>true</code> allows the encoded form of <code>value</code> to extend beyond\nthe end of <code>buf</code>, but the resulting behavior is undefined.</p>\n<pre><code class=\"lang-js\">const buf = Buffer.allocUnsafe(8);\n\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>\n</code></pre>\n"
},
{
"textRaw": "buf.writeFloatBE(value, offset[, noAssert])",
"type": "method",
"name": "writeFloatBE",
"meta": {
"added": [
"v0.11.15"
],
"changes": []
},
"signatures": [
{
"return": {
"textRaw": "Returns: {integer} `offset` plus the number of bytes written. ",
"name": "return",
"type": "integer",
"desc": "`offset` plus the number of bytes written."
},
"params": [
{
"textRaw": "`value` {number} Number to be written to `buf`. ",
"name": "value",
"type": "number",
"desc": "Number to be written to `buf`."
},
{
"textRaw": "`offset` {integer} Number of bytes to skip before starting to write. Must satisfy: `0 <= offset <= buf.length - 4`. ",
"name": "offset",
"type": "integer",
"desc": "Number of bytes to skip before starting to write. Must satisfy: `0 <= offset <= buf.length - 4`."
},
{
"textRaw": "`noAssert` {boolean} Skip `value` and `offset` validation? **Default:** `false` ",
"name": "noAssert",
"type": "boolean",
"desc": "Skip `value` and `offset` validation? **Default:** `false`",
"optional": true
}
]
},
{
"params": [
{
"name": "value"
},
{
"name": "offset"
},
{
"name": "noAssert",
"optional": true
}
]
},
{
"params": [
{
"name": "value"
},
{
"name": "offset"
},
{
"name": "noAssert",
"optional": true
}
]
}
],
"desc": "<p>Writes <code>value</code> to <code>buf</code> at the specified <code>offset</code> with specified endian\nformat (<code>writeFloatBE()</code> writes big endian, <code>writeFloatLE()</code> writes little\nendian). <code>value</code> <em>should</em> be a valid 32-bit float. Behavior is undefined when\n<code>value</code> is anything other than a 32-bit float.</p>\n<p>Setting <code>noAssert</code> to <code>true</code> allows the encoded form of <code>value</code> to extend beyond\nthe end of <code>buf</code>, but the resulting behavior is undefined.</p>\n<pre><code class=\"lang-js\">const buf = Buffer.allocUnsafe(4);\n\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>\n</code></pre>\n"
},
{
"textRaw": "buf.writeFloatLE(value, offset[, noAssert])",
"type": "method",
"name": "writeFloatLE",
"meta": {
"added": [
"v0.11.15"
],
"changes": []
},
"signatures": [
{
"return": {
"textRaw": "Returns: {integer} `offset` plus the number of bytes written. ",
"name": "return",
"type": "integer",
"desc": "`offset` plus the number of bytes written."
},
"params": [
{
"textRaw": "`value` {number} Number to be written to `buf`. ",
"name": "value",
"type": "number",
"desc": "Number to be written to `buf`."
},
{
"textRaw": "`offset` {integer} Number of bytes to skip before starting to write. Must satisfy: `0 <= offset <= buf.length - 4`. ",
"name": "offset",
"type": "integer",
"desc": "Number of bytes to skip before starting to write. Must satisfy: `0 <= offset <= buf.length - 4`."
},
{
"textRaw": "`noAssert` {boolean} Skip `value` and `offset` validation? **Default:** `false` ",
"name": "noAssert",
"type": "boolean",
"desc": "Skip `value` and `offset` validation? **Default:** `false`",
"optional": true
}
]
},
{
"params": [
{
"name": "value"
},
{
"name": "offset"
},
{
"name": "noAssert",
"optional": true
}
]
}
],
"desc": "<p>Writes <code>value</code> to <code>buf</code> at the specified <code>offset</code> with specified endian\nformat (<code>writeFloatBE()</code> writes big endian, <code>writeFloatLE()</code> writes little\nendian). <code>value</code> <em>should</em> be a valid 32-bit float. Behavior is undefined when\n<code>value</code> is anything other than a 32-bit float.</p>\n<p>Setting <code>noAssert</code> to <code>true</code> allows the encoded form of <code>value</code> to extend beyond\nthe end of <code>buf</code>, but the resulting behavior is undefined.</p>\n<pre><code class=\"lang-js\">const buf = Buffer.allocUnsafe(4);\n\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>\n</code></pre>\n"
},
{
"textRaw": "buf.writeInt8(value, offset[, noAssert])",
"type": "method",
"name": "writeInt8",
"meta": {
"added": [
"v0.5.0"
],
"changes": []
},
"signatures": [
{
"return": {
"textRaw": "Returns: {integer} `offset` plus the number of bytes written. ",
"name": "return",
"type": "integer",
"desc": "`offset` plus the number of bytes written."
},
"params": [
{
"textRaw": "`value` {integer} Number to be written to `buf`. ",
"name": "value",
"type": "integer",
"desc": "Number to be written to `buf`."
},
{
"textRaw": "`offset` {integer} Number of bytes to skip before starting to write. Must satisfy: `0 <= offset <= buf.length - 1`. ",
"name": "offset",
"type": "integer",
"desc": "Number of bytes to skip before starting to write. Must satisfy: `0 <= offset <= buf.length - 1`."
},
{
"textRaw": "`noAssert` {boolean} Skip `value` and `offset` validation? **Default:** `false` ",
"name": "noAssert",
"type": "boolean",
"desc": "Skip `value` and `offset` validation? **Default:** `false`",
"optional": true
}
]
},
{
"params": [
{
"name": "value"
},
{
"name": "offset"
},
{
"name": "noAssert",
"optional": true
}
]
}
],
"desc": "<p>Writes <code>value</code> to <code>buf</code> at the specified <code>offset</code>. <code>value</code> <em>should</em> be a valid\nsigned 8-bit integer. Behavior is undefined when <code>value</code> is anything other than\na signed 8-bit integer.</p>\n<p>Setting <code>noAssert</code> to <code>true</code> allows the encoded form of <code>value</code> to extend beyond\nthe end of <code>buf</code>, but the resulting behavior is undefined.</p>\n<p><code>value</code> is interpreted and written as a two's complement signed integer.</p>\n<pre><code class=\"lang-js\">const buf = Buffer.allocUnsafe(2);\n\nbuf.writeInt8(2, 0);\nbuf.writeInt8(-2, 1);\n\nconsole.log(buf);\n// Prints: <Buffer 02 fe>\n</code></pre>\n"
},
{
"textRaw": "buf.writeInt16BE(value, offset[, noAssert])",
"type": "method",
"name": "writeInt16BE",
"meta": {
"added": [
"v0.5.5"
],
"changes": []
},
"signatures": [
{
"return": {
"textRaw": "Returns: {integer} `offset` plus the number of bytes written. ",
"name": "return",
"type": "integer",
"desc": "`offset` plus the number of bytes written."
},
"params": [
{
"textRaw": "`value` {integer} Number to be written to `buf`. ",
"name": "value",
"type": "integer",
"desc": "Number to be written to `buf`."
},
{
"textRaw": "`offset` {integer} Number of bytes to skip before starting to write. Must satisfy: `0 <= offset <= buf.length - 2`. ",
"name": "offset",
"type": "integer",
"desc": "Number of bytes to skip before starting to write. Must satisfy: `0 <= offset <= buf.length - 2`."
},
{
"textRaw": "`noAssert` {boolean} Skip `value` and `offset` validation? **Default:** `false` ",
"name": "noAssert",
"type": "boolean",
"desc": "Skip `value` and `offset` validation? **Default:** `false`",
"optional": true
}
]
},
{
"params": [
{
"name": "value"
},
{
"name": "offset"
},
{
"name": "noAssert",
"optional": true
}
]
},
{
"params": [
{
"name": "value"
},
{
"name": "offset"
},
{
"name": "noAssert",
"optional": true
}
]
}
],
"desc": "<p>Writes <code>value</code> to <code>buf</code> at the specified <code>offset</code> with specified endian\nformat (<code>writeInt16BE()</code> writes big endian, <code>writeInt16LE()</code> writes little\nendian). <code>value</code> <em>should</em> be a valid signed 16-bit integer. Behavior is undefined\nwhen <code>value</code> is anything other than a signed 16-bit integer.</p>\n<p>Setting <code>noAssert</code> to <code>true</code> allows the encoded form of <code>value</code> to extend beyond\nthe end of <code>buf</code>, but the resulting behavior is undefined.</p>\n<p><code>value</code> is interpreted and written as a two's complement signed integer.</p>\n<pre><code class=\"lang-js\">const buf = Buffer.allocUnsafe(4);\n\nbuf.writeInt16BE(0x0102, 0);\nbuf.writeInt16LE(0x0304, 2);\n\nconsole.log(buf);\n// Prints: <Buffer 01 02 04 03>\n</code></pre>\n"
},
{
"textRaw": "buf.writeInt16LE(value, offset[, noAssert])",
"type": "method",
"name": "writeInt16LE",
"meta": {
"added": [
"v0.5.5"
],
"changes": []
},
"signatures": [
{
"return": {
"textRaw": "Returns: {integer} `offset` plus the number of bytes written. ",
"name": "return",
"type": "integer",
"desc": "`offset` plus the number of bytes written."
},
"params": [
{
"textRaw": "`value` {integer} Number to be written to `buf`. ",
"name": "value",
"type": "integer",
"desc": "Number to be written to `buf`."
},
{
"textRaw": "`offset` {integer} Number of bytes to skip before starting to write. Must satisfy: `0 <= offset <= buf.length - 2`. ",
"name": "offset",
"type": "integer",
"desc": "Number of bytes to skip before starting to write. Must satisfy: `0 <= offset <= buf.length - 2`."
},
{
"textRaw": "`noAssert` {boolean} Skip `value` and `offset` validation? **Default:** `false` ",
"name": "noAssert",
"type": "boolean",
"desc": "Skip `value` and `offset` validation? **Default:** `false`",
"optional": true
}
]
},
{
"params": [
{
"name": "value"
},
{
"name": "offset"
},
{
"name": "noAssert",
"optional": true
}
]
}
],
"desc": "<p>Writes <code>value</code> to <code>buf</code> at the specified <code>offset</code> with specified endian\nformat (<code>writeInt16BE()</code> writes big endian, <code>writeInt16LE()</code> writes little\nendian). <code>value</code> <em>should</em> be a valid signed 16-bit integer. Behavior is undefined\nwhen <code>value</code> is anything other than a signed 16-bit integer.</p>\n<p>Setting <code>noAssert</code> to <code>true</code> allows the encoded form of <code>value</code> to extend beyond\nthe end of <code>buf</code>, but the resulting behavior is undefined.</p>\n<p><code>value</code> is interpreted and written as a two's complement signed integer.</p>\n<pre><code class=\"lang-js\">const buf = Buffer.allocUnsafe(4);\n\nbuf.writeInt16BE(0x0102, 0);\nbuf.writeInt16LE(0x0304, 2);\n\nconsole.log(buf);\n// Prints: <Buffer 01 02 04 03>\n</code></pre>\n"
},
{
"textRaw": "buf.writeInt32BE(value, offset[, noAssert])",
"type": "method",
"name": "writeInt32BE",
"meta": {
"added": [
"v0.5.5"
],
"changes": []
},
"signatures": [
{
"return": {
"textRaw": "Returns: {integer} `offset` plus the number of bytes written. ",
"name": "return",
"type": "integer",
"desc": "`offset` plus the number of bytes written."
},
"params": [
{
"textRaw": "`value` {integer} Number to be written to `buf`. ",
"name": "value",
"type": "integer",
"desc": "Number to be written to `buf`."
},
{
"textRaw": "`offset` {integer} Number of bytes to skip before starting to write. Must satisfy: `0 <= offset <= buf.length - 4`. ",
"name": "offset",
"type": "integer",
"desc": "Number of bytes to skip before starting to write. Must satisfy: `0 <= offset <= buf.length - 4`."
},
{
"textRaw": "`noAssert` {boolean} Skip `value` and `offset` validation? **Default:** `false` ",
"name": "noAssert",
"type": "boolean",
"desc": "Skip `value` and `offset` validation? **Default:** `false`",
"optional": true
}
]
},
{
"params": [
{
"name": "value"
},
{
"name": "offset"
},
{
"name": "noAssert",
"optional": true
}
]
},
{
"params": [
{
"name": "value"
},
{
"name": "offset"
},
{
"name": "noAssert",
"optional": true
}
]
}
],
"desc": "<p>Writes <code>value</code> to <code>buf</code> at the specified <code>offset</code> with specified endian\nformat (<code>writeInt32BE()</code> writes big endian, <code>writeInt32LE()</code> writes little\nendian). <code>value</code> <em>should</em> be a valid signed 32-bit integer. Behavior is undefined\nwhen <code>value</code> is anything other than a signed 32-bit integer.</p>\n<p>Setting <code>noAssert</code> to <code>true</code> allows the encoded form of <code>value</code> to extend beyond\nthe end of <code>buf</code>, but the resulting behavior is undefined.</p>\n<p><code>value</code> is interpreted and written as a two's complement signed integer.</p>\n<pre><code class=\"lang-js\">const buf = Buffer.allocUnsafe(8);\n\nbuf.writeInt32BE(0x01020304, 0);\nbuf.writeInt32LE(0x05060708, 4);\n\nconsole.log(buf);\n// Prints: <Buffer 01 02 03 04 08 07 06 05>\n</code></pre>\n"
},
{
"textRaw": "buf.writeInt32LE(value, offset[, noAssert])",
"type": "method",
"name": "writeInt32LE",
"meta": {
"added": [
"v0.5.5"
],
"changes": []
},
"signatures": [
{
"return": {
"textRaw": "Returns: {integer} `offset` plus the number of bytes written. ",
"name": "return",
"type": "integer",
"desc": "`offset` plus the number of bytes written."
},
"params": [
{
"textRaw": "`value` {integer} Number to be written to `buf`. ",
"name": "value",
"type": "integer",
"desc": "Number to be written to `buf`."
},
{
"textRaw": "`offset` {integer} Number of bytes to skip before starting to write. Must satisfy: `0 <= offset <= buf.length - 4`. ",
"name": "offset",
"type": "integer",
"desc": "Number of bytes to skip before starting to write. Must satisfy: `0 <= offset <= buf.length - 4`."
},
{
"textRaw": "`noAssert` {boolean} Skip `value` and `offset` validation? **Default:** `false` ",
"name": "noAssert",
"type": "boolean",
"desc": "Skip `value` and `offset` validation? **Default:** `false`",
"optional": true
}
]
},
{
"params": [
{
"name": "value"
},
{
"name": "offset"
},
{
"name": "noAssert",
"optional": true
}
]
}
],
"desc": "<p>Writes <code>value</code> to <code>buf</code> at the specified <code>offset</code> with specified endian\nformat (<code>writeInt32BE()</code> writes big endian, <code>writeInt32LE()</code> writes little\nendian). <code>value</code> <em>should</em> be a valid signed 32-bit integer. Behavior is undefined\nwhen <code>value</code> is anything other than a signed 32-bit integer.</p>\n<p>Setting <code>noAssert</code> to <code>true</code> allows the encoded form of <code>value</code> to extend beyond\nthe end of <code>buf</code>, but the resulting behavior is undefined.</p>\n<p><code>value</code> is interpreted and written as a two's complement signed integer.</p>\n<pre><code class=\"lang-js\">const buf = Buffer.allocUnsafe(8);\n\nbuf.writeInt32BE(0x01020304, 0);\nbuf.writeInt32LE(0x05060708, 4);\n\nconsole.log(buf);\n// Prints: <Buffer 01 02 03 04 08 07 06 05>\n</code></pre>\n"
},
{
"textRaw": "buf.writeIntBE(value, offset, byteLength[, noAssert])",
"type": "method",
"name": "writeIntBE",
"meta": {
"added": [
"v0.11.15"
],
"changes": []
},
"signatures": [
{
"return": {
"textRaw": "Returns: {integer} `offset` plus the number of bytes written. ",
"name": "return",
"type": "integer",
"desc": "`offset` plus the number of bytes written."
},
"params": [
{
"textRaw": "`value` {integer} Number to be written to `buf`. ",
"name": "value",
"type": "integer",
"desc": "Number to be written to `buf`."
},
{
"textRaw": "`offset` {integer} Number of bytes to skip before starting to write. Must satisfy: `0 <= offset <= buf.length - byteLength`. ",
"name": "offset",
"type": "integer",
"desc": "Number of bytes to skip before starting to write. Must satisfy: `0 <= offset <= buf.length - byteLength`."
},
{
"textRaw": "`byteLength` {integer} Number of bytes to write. Must satisfy: `0 < byteLength <= 6`. ",
"name": "byteLength",
"type": "integer",
"desc": "Number of bytes to write. Must satisfy: `0 < byteLength <= 6`."
},
{
"textRaw": "`noAssert` {boolean} Skip `value`, `offset`, and `byteLength` validation? **Default:** `false` ",
"name": "noAssert",
"type": "boolean",
"desc": "Skip `value`, `offset`, and `byteLength` validation? **Default:** `false`",
"optional": true
}
]
},
{
"params": [
{
"name": "value"
},
{
"name": "offset"
},
{
"name": "byteLength"
},
{
"name": "noAssert",
"optional": true
}
]
},
{
"params": [
{
"name": "value"
},
{
"name": "offset"
},
{
"name": "byteLength"
},
{
"name": "noAssert",
"optional": true
}
]
}
],
"desc": "<p>Writes <code>byteLength</code> bytes of <code>value</code> to <code>buf</code> at the specified <code>offset</code>.\nSupports up to 48 bits of accuracy. Behavior is undefined when <code>value</code> is\nanything other than a signed integer.</p>\n<p>Setting <code>noAssert</code> to <code>true</code> allows the encoded form of <code>value</code> to extend beyond\nthe end of <code>buf</code>, but the resulting behavior is undefined.</p>\n<pre><code class=\"lang-js\">const buf = Buffer.allocUnsafe(6);\n\nbuf.writeIntBE(0x1234567890ab, 0, 6);\n\nconsole.log(buf);\n// Prints: <Buffer 12 34 56 78 90 ab>\n\nbuf.writeIntLE(0x1234567890ab, 0, 6);\n\nconsole.log(buf);\n// Prints: <Buffer ab 90 78 56 34 12>\n</code></pre>\n"
},
{
"textRaw": "buf.writeIntLE(value, offset, byteLength[, noAssert])",
"type": "method",
"name": "writeIntLE",
"meta": {
"added": [
"v0.11.15"
],
"changes": []
},
"signatures": [
{
"return": {
"textRaw": "Returns: {integer} `offset` plus the number of bytes written. ",
"name": "return",
"type": "integer",
"desc": "`offset` plus the number of bytes written."
},
"params": [
{
"textRaw": "`value` {integer} Number to be written to `buf`. ",
"name": "value",
"type": "integer",
"desc": "Number to be written to `buf`."
},
{
"textRaw": "`offset` {integer} Number of bytes to skip before starting to write. Must satisfy: `0 <= offset <= buf.length - byteLength`. ",
"name": "offset",
"type": "integer",
"desc": "Number of bytes to skip before starting to write. Must satisfy: `0 <= offset <= buf.length - byteLength`."
},
{
"textRaw": "`byteLength` {integer} Number of bytes to write. Must satisfy: `0 < byteLength <= 6`. ",
"name": "byteLength",
"type": "integer",
"desc": "Number of bytes to write. Must satisfy: `0 < byteLength <= 6`."
},
{
"textRaw": "`noAssert` {boolean} Skip `value`, `offset`, and `byteLength` validation? **Default:** `false` ",
"name": "noAssert",
"type": "boolean",
"desc": "Skip `value`, `offset`, and `byteLength` validation? **Default:** `false`",
"optional": true
}
]
},
{
"params": [
{
"name": "value"
},
{
"name": "offset"
},
{
"name": "byteLength"
},
{
"name": "noAssert",
"optional": true
}
]
}
],
"desc": "<p>Writes <code>byteLength</code> bytes of <code>value</code> to <code>buf</code> at the specified <code>offset</code>.\nSupports up to 48 bits of accuracy. Behavior is undefined when <code>value</code> is\nanything other than a signed integer.</p>\n<p>Setting <code>noAssert</code> to <code>true</code> allows the encoded form of <code>value</code> to extend beyond\nthe end of <code>buf</code>, but the resulting behavior is undefined.</p>\n<pre><code class=\"lang-js\">const buf = Buffer.allocUnsafe(6);\n\nbuf.writeIntBE(0x1234567890ab, 0, 6);\n\nconsole.log(buf);\n// Prints: <Buffer 12 34 56 78 90 ab>\n\nbuf.writeIntLE(0x1234567890ab, 0, 6);\n\nconsole.log(buf);\n// Prints: <Buffer ab 90 78 56 34 12>\n</code></pre>\n"
},
{
"textRaw": "buf.writeUInt8(value, offset[, noAssert])",
"type": "method",
"name": "writeUInt8",
"meta": {
"added": [
"v0.5.0"
],
"changes": []
},
"signatures": [
{
"return": {
"textRaw": "Returns: {integer} `offset` plus the number of bytes written. ",
"name": "return",
"type": "integer",
"desc": "`offset` plus the number of bytes written."
},
"params": [
{
"textRaw": "`value` {integer} Number to be written to `buf`. ",
"name": "value",
"type": "integer",
"desc": "Number to be written to `buf`."
},
{
"textRaw": "`offset` {integer} Number of bytes to skip before starting to write. Must satisfy: `0 <= offset <= buf.length - 1`. ",
"name": "offset",
"type": "integer",
"desc": "Number of bytes to skip before starting to write. Must satisfy: `0 <= offset <= buf.length - 1`."
},
{
"textRaw": "`noAssert` {boolean} Skip `value` and `offset` validation? **Default:** `false` ",
"name": "noAssert",
"type": "boolean",
"desc": "Skip `value` and `offset` validation? **Default:** `false`",
"optional": true
}
]
},
{
"params": [
{
"name": "value"
},
{
"name": "offset"
},
{
"name": "noAssert",
"optional": true
}
]
}
],
"desc": "<p>Writes <code>value</code> to <code>buf</code> at the specified <code>offset</code>. <code>value</code> <em>should</em> be a\nvalid unsigned 8-bit integer. Behavior is undefined when <code>value</code> is anything\nother than an unsigned 8-bit integer.</p>\n<p>Setting <code>noAssert</code> to <code>true</code> allows the encoded form of <code>value</code> to extend beyond\nthe end of <code>buf</code>, but the resulting behavior is undefined.</p>\n<pre><code class=\"lang-js\">const 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>\n</code></pre>\n"
},
{
"textRaw": "buf.writeUInt16BE(value, offset[, noAssert])",
"type": "method",
"name": "writeUInt16BE",
"meta": {
"added": [
"v0.5.5"
],
"changes": []
},
"signatures": [
{
"return": {
"textRaw": "Returns: {integer} `offset` plus the number of bytes written. ",
"name": "return",
"type": "integer",
"desc": "`offset` plus the number of bytes written."
},
"params": [
{
"textRaw": "`value` {integer} Number to be written to `buf`. ",
"name": "value",
"type": "integer",
"desc": "Number to be written to `buf`."
},
{
"textRaw": "`offset` {integer} Number of bytes to skip before starting to write. Must satisfy: `0 <= offset <= buf.length - 2`. ",
"name": "offset",
"type": "integer",
"desc": "Number of bytes to skip before starting to write. Must satisfy: `0 <= offset <= buf.length - 2`."
},
{
"textRaw": "`noAssert` {boolean} Skip `value` and `offset` validation? **Default:** `false` ",
"name": "noAssert",
"type": "boolean",
"desc": "Skip `value` and `offset` validation? **Default:** `false`",
"optional": true
}
]
},
{
"params": [
{
"name": "value"
},
{
"name": "offset"
},
{
"name": "noAssert",
"optional": true
}
]
},
{
"params": [
{
"name": "value"
},
{
"name": "offset"
},
{
"name": "noAssert",
"optional": true
}
]
}
],
"desc": "<p>Writes <code>value</code> to <code>buf</code> at the specified <code>offset</code> with specified endian\nformat (<code>writeUInt16BE()</code> writes big endian, <code>writeUInt16LE()</code> writes little\nendian). <code>value</code> should be a valid unsigned 16-bit integer. Behavior is\nundefined when <code>value</code> is anything other than an unsigned 16-bit integer.</p>\n<p>Setting <code>noAssert</code> to <code>true</code> allows the encoded form of <code>value</code> to extend beyond\nthe end of <code>buf</code>, but the resulting behavior is undefined.</p>\n<pre><code class=\"lang-js\">const buf = Buffer.allocUnsafe(4);\n\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>\n</code></pre>\n"
},
{
"textRaw": "buf.writeUInt16LE(value, offset[, noAssert])",
"type": "method",
"name": "writeUInt16LE",
"meta": {
"added": [
"v0.5.5"
],
"changes": []
},
"signatures": [
{
"return": {
"textRaw": "Returns: {integer} `offset` plus the number of bytes written. ",
"name": "return",
"type": "integer",
"desc": "`offset` plus the number of bytes written."
},
"params": [
{
"textRaw": "`value` {integer} Number to be written to `buf`. ",
"name": "value",
"type": "integer",
"desc": "Number to be written to `buf`."
},
{
"textRaw": "`offset` {integer} Number of bytes to skip before starting to write. Must satisfy: `0 <= offset <= buf.length - 2`. ",
"name": "offset",
"type": "integer",
"desc": "Number of bytes to skip before starting to write. Must satisfy: `0 <= offset <= buf.length - 2`."
},
{
"textRaw": "`noAssert` {boolean} Skip `value` and `offset` validation? **Default:** `false` ",
"name": "noAssert",
"type": "boolean",
"desc": "Skip `value` and `offset` validation? **Default:** `false`",
"optional": true
}
]
},
{
"params": [
{
"name": "value"
},
{
"name": "offset"
},
{
"name": "noAssert",
"optional": true
}
]
}
],
"desc": "<p>Writes <code>value</code> to <code>buf</code> at the specified <code>offset</code> with specified endian\nformat (<code>writeUInt16BE()</code> writes big endian, <code>writeUInt16LE()</code> writes little\nendian). <code>value</code> should be a valid unsigned 16-bit integer. Behavior is\nundefined when <code>value</code> is anything other than an unsigned 16-bit integer.</p>\n<p>Setting <code>noAssert</code> to <code>true</code> allows the encoded form of <code>value</code> to extend beyond\nthe end of <code>buf</code>, but the resulting behavior is undefined.</p>\n<pre><code class=\"lang-js\">const buf = Buffer.allocUnsafe(4);\n\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>\n</code></pre>\n"
},
{
"textRaw": "buf.writeUInt32BE(value, offset[, noAssert])",
"type": "method",
"name": "writeUInt32BE",
"meta": {
"added": [
"v0.5.5"
],
"changes": []
},
"signatures": [
{
"return": {
"textRaw": "Returns: {integer} `offset` plus the number of bytes written. ",
"name": "return",
"type": "integer",
"desc": "`offset` plus the number of bytes written."
},
"params": [
{
"textRaw": "`value` {integer} Number to be written to `buf`. ",
"name": "value",
"type": "integer",
"desc": "Number to be written to `buf`."
},
{
"textRaw": "`offset` {integer} Number of bytes to skip before starting to write. Must satisfy: `0 <= offset <= buf.length - 4`. ",
"name": "offset",
"type": "integer",
"desc": "Number of bytes to skip before starting to write. Must satisfy: `0 <= offset <= buf.length - 4`."
},
{
"textRaw": "`noAssert` {boolean} Skip `value` and `offset` validation? **Default:** `false` ",
"name": "noAssert",
"type": "boolean",
"desc": "Skip `value` and `offset` validation? **Default:** `false`",
"optional": true
}
]
},
{
"params": [
{
"name": "value"
},
{
"name": "offset"
},
{
"name": "noAssert",
"optional": true
}
]
},
{
"params": [
{
"name": "value"
},
{
"name": "offset"
},
{
"name": "noAssert",
"optional": true
}
]
}
],
"desc": "<p>Writes <code>value</code> to <code>buf</code> at the specified <code>offset</code> with specified endian\nformat (<code>writeUInt32BE()</code> writes big endian, <code>writeUInt32LE()</code> writes little\nendian). <code>value</code> should be a valid unsigned 32-bit integer. Behavior is\nundefined when <code>value</code> is anything other than an unsigned 32-bit integer.</p>\n<p>Setting <code>noAssert</code> to <code>true</code> allows the encoded form of <code>value</code> to extend beyond\nthe end of <code>buf</code>, but the resulting behavior is undefined.</p>\n<pre><code class=\"lang-js\">const buf = Buffer.allocUnsafe(4);\n\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>\n</code></pre>\n"
},
{
"textRaw": "buf.writeUInt32LE(value, offset[, noAssert])",
"type": "method",
"name": "writeUInt32LE",
"meta": {
"added": [
"v0.5.5"
],
"changes": []
},
"signatures": [
{
"return": {
"textRaw": "Returns: {integer} `offset` plus the number of bytes written. ",
"name": "return",
"type": "integer",
"desc": "`offset` plus the number of bytes written."
},
"params": [
{
"textRaw": "`value` {integer} Number to be written to `buf`. ",
"name": "value",
"type": "integer",
"desc": "Number to be written to `buf`."
},
{
"textRaw": "`offset` {integer} Number of bytes to skip before starting to write. Must satisfy: `0 <= offset <= buf.length - 4`. ",
"name": "offset",
"type": "integer",
"desc": "Number of bytes to skip before starting to write. Must satisfy: `0 <= offset <= buf.length - 4`."
},
{
"textRaw": "`noAssert` {boolean} Skip `value` and `offset` validation? **Default:** `false` ",
"name": "noAssert",
"type": "boolean",
"desc": "Skip `value` and `offset` validation? **Default:** `false`",
"optional": true
}
]
},
{
"params": [
{
"name": "value"
},
{
"name": "offset"
},
{
"name": "noAssert",
"optional": true
}
]
}
],
"desc": "<p>Writes <code>value</code> to <code>buf</code> at the specified <code>offset</code> with specified endian\nformat (<code>writeUInt32BE()</code> writes big endian, <code>writeUInt32LE()</code> writes little\nendian). <code>value</code> should be a valid unsigned 32-bit integer. Behavior is\nundefined when <code>value</code> is anything other than an unsigned 32-bit integer.</p>\n<p>Setting <code>noAssert</code> to <code>true</code> allows the encoded form of <code>value</code> to extend beyond\nthe end of <code>buf</code>, but the resulting behavior is undefined.</p>\n<pre><code class=\"lang-js\">const buf = Buffer.allocUnsafe(4);\n\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>\n</code></pre>\n"
},
{
"textRaw": "buf.writeUIntBE(value, offset, byteLength[, noAssert])",
"type": "method",
"name": "writeUIntBE",
"meta": {
"added": [
"v0.5.5"
],
"changes": []
},
"signatures": [
{
"return": {
"textRaw": "Returns: {integer} `offset` plus the number of bytes written. ",
"name": "return",
"type": "integer",
"desc": "`offset` plus the number of bytes written."
},
"params": [
{
"textRaw": "`value` {integer} Number to be written to `buf`. ",
"name": "value",
"type": "integer",
"desc": "Number to be written to `buf`."
},
{
"textRaw": "`offset` {integer} Number of bytes to skip before starting to write. Must satisfy: `0 <= offset <= buf.length - byteLength`. ",
"name": "offset",
"type": "integer",
"desc": "Number of bytes to skip before starting to write. Must satisfy: `0 <= offset <= buf.length - byteLength`."
},
{
"textRaw": "`byteLength` {integer} Number of bytes to write. Must satisfy: `0 < byteLength <= 6`. ",
"name": "byteLength",
"type": "integer",
"desc": "Number of bytes to write. Must satisfy: `0 < byteLength <= 6`."
},
{
"textRaw": "`noAssert` {boolean} Skip `value`, `offset`, and `byteLength` validation? **Default:** `false` ",
"name": "noAssert",
"type": "boolean",
"desc": "Skip `value`, `offset`, and `byteLength` validation? **Default:** `false`",
"optional": true
}
]
},
{
"params": [
{
"name": "value"
},
{
"name": "offset"
},
{
"name": "byteLength"
},
{
"name": "noAssert",
"optional": true
}
]
},
{
"params": [
{
"name": "value"
},
{
"name": "offset"
},
{
"name": "byteLength"
},
{
"name": "noAssert",
"optional": true
}
]
}
],
"desc": "<p>Writes <code>byteLength</code> bytes of <code>value</code> to <code>buf</code> at the specified <code>offset</code>.\nSupports up to 48 bits of accuracy. Behavior is undefined when <code>value</code> is\nanything other than an unsigned integer.</p>\n<p>Setting <code>noAssert</code> to <code>true</code> allows the encoded form of <code>value</code> to extend beyond\nthe end of <code>buf</code>, but the resulting behavior is undefined.</p>\n<pre><code class=\"lang-js\">const buf = Buffer.allocUnsafe(6);\n\nbuf.writeUIntBE(0x1234567890ab, 0, 6);\n\nconsole.log(buf);\n// Prints: <Buffer 12 34 56 78 90 ab>\n\nbuf.writeUIntLE(0x1234567890ab, 0, 6);\n\nconsole.log(buf);\n// Prints: <Buffer ab 90 78 56 34 12>\n</code></pre>\n"
},
{
"textRaw": "buf.writeUIntLE(value, offset, byteLength[, noAssert])",
"type": "method",
"name": "writeUIntLE",
"meta": {
"added": [
"v0.5.5"
],
"changes": []
},
"signatures": [
{
"return": {
"textRaw": "Returns: {integer} `offset` plus the number of bytes written. ",
"name": "return",
"type": "integer",
"desc": "`offset` plus the number of bytes written."
},
"params": [
{
"textRaw": "`value` {integer} Number to be written to `buf`. ",
"name": "value",
"type": "integer",
"desc": "Number to be written to `buf`."
},
{
"textRaw": "`offset` {integer} Number of bytes to skip before starting to write. Must satisfy: `0 <= offset <= buf.length - byteLength`. ",
"name": "offset",
"type": "integer",
"desc": "Number of bytes to skip before starting to write. Must satisfy: `0 <= offset <= buf.length - byteLength`."
},
{
"textRaw": "`byteLength` {integer} Number of bytes to write. Must satisfy: `0 < byteLength <= 6`. ",
"name": "byteLength",
"type": "integer",
"desc": "Number of bytes to write. Must satisfy: `0 < byteLength <= 6`."
},
{
"textRaw": "`noAssert` {boolean} Skip `value`, `offset`, and `byteLength` validation? **Default:** `false` ",
"name": "noAssert",
"type": "boolean",
"desc": "Skip `value`, `offset`, and `byteLength` validation? **Default:** `false`",
"optional": true
}
]
},
{
"params": [
{
"name": "value"
},
{
"name": "offset"
},
{
"name": "byteLength"
},
{
"name": "noAssert",
"optional": true
}
]
}
],
"desc": "<p>Writes <code>byteLength</code> bytes of <code>value</code> to <code>buf</code> at the specified <code>offset</code>.\nSupports up to 48 bits of accuracy. Behavior is undefined when <code>value</code> is\nanything other than an unsigned integer.</p>\n<p>Setting <code>noAssert</code> to <code>true</code> allows the encoded form of <code>value</code> to extend beyond\nthe end of <code>buf</code>, but the resulting behavior is undefined.</p>\n<pre><code class=\"lang-js\">const buf = Buffer.allocUnsafe(6);\n\nbuf.writeUIntBE(0x1234567890ab, 0, 6);\n\nconsole.log(buf);\n// Prints: <Buffer 12 34 56 78 90 ab>\n\nbuf.writeUIntLE(0x1234567890ab, 0, 6);\n\nconsole.log(buf);\n// Prints: <Buffer ab 90 78 56 34 12>\n</code></pre>\n"
}
],
"signatures": [
{
"params": [
{
"textRaw": "`array` {integer[]} An array of bytes to copy from. ",
"name": "array",
"type": "integer[]",
"desc": "An array of bytes to copy from."
}
],
"desc": "<p>Allocates a new <code>Buffer</code> using an <code>array</code> of octets.</p>\n<pre><code class=\"lang-js\">// Creates a new Buffer containing the UTF-8 bytes of the string 'buffer'\nconst buf = new Buffer([0x62, 0x75, 0x66, 0x66, 0x65, 0x72]);\n</code></pre>\n"
},
{
"params": [
{
"name": "array"
}
],
"desc": "<p>Allocates a new <code>Buffer</code> using an <code>array</code> of octets.</p>\n<pre><code class=\"lang-js\">// Creates a new Buffer containing the UTF-8 bytes of the string 'buffer'\nconst buf = new Buffer([0x62, 0x75, 0x66, 0x66, 0x65, 0x72]);\n</code></pre>\n"
},
{
"params": [
{
"textRaw": "`arrayBuffer` {ArrayBuffer|SharedArrayBuffer} An [`ArrayBuffer`], [`SharedArrayBuffer`] or the `.buffer` property of a [`TypedArray`]. ",
"name": "arrayBuffer",
"type": "ArrayBuffer|SharedArrayBuffer",
"desc": "An [`ArrayBuffer`], [`SharedArrayBuffer`] or the `.buffer` property of a [`TypedArray`]."
},
{
"textRaw": "`byteOffset` {integer} Index of first byte to expose. **Default:** `0` ",
"name": "byteOffset",
"type": "integer",
"desc": "Index of first byte to expose. **Default:** `0`",
"optional": true
},
{
"textRaw": "`length` {integer} Number of bytes to expose. **Default:** `arrayBuffer.length - byteOffset` ",
"name": "length",
"type": "integer",
"desc": "Number of bytes to expose. **Default:** `arrayBuffer.length - byteOffset`",
"optional": true
}
],
"desc": "<p>Stability: 0 - Deprecated: Use\n<a href=\"#buffer_class_method_buffer_from_arraybuffer_byteoffset_length\"><code>Buffer.from(arrayBuffer[, byteOffset [, length]])</code></a>\ninstead.</p>\n<p>This creates a view of the <a href=\"https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer\"><code>ArrayBuffer</code></a> or <a href=\"https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/SharedArrayBuffer\"><code>SharedArrayBuffer</code></a> without\ncopying the underlying memory. For example, when passed a reference to the\n<code>.buffer</code> property of a <a href=\"https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray\"><code>TypedArray</code></a> instance, the newly created <code>Buffer</code> will\nshare the same allocated memory as the <a href=\"https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray\"><code>TypedArray</code></a>.</p>\n<p>The optional <code>byteOffset</code> and <code>length</code> arguments specify a memory range within\nthe <code>arrayBuffer</code> that will be shared by the <code>Buffer</code>.</p>\n<pre><code class=\"lang-js\">const arr = new Uint16Array(2);\n\narr[0] = 5000;\narr[1] = 4000;\n\n// Shares memory with `arr`\nconst buf = new Buffer(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>\n</code></pre>\n"
},
{
"params": [
{
"name": "arrayBuffer"
},
{
"name": "byteOffset",
"optional": true
},
{
"name": "length",
"optional": true
}
],
"desc": "<p>Stability: 0 - Deprecated: Use\n<a href=\"#buffer_class_method_buffer_from_arraybuffer_byteoffset_length\"><code>Buffer.from(arrayBuffer[, byteOffset [, length]])</code></a>\ninstead.</p>\n<p>This creates a view of the <a href=\"https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer\"><code>ArrayBuffer</code></a> or <a href=\"https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/SharedArrayBuffer\"><code>SharedArrayBuffer</code></a> without\ncopying the underlying memory. For example, when passed a reference to the\n<code>.buffer</code> property of a <a href=\"https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray\"><code>TypedArray</code></a> instance, the newly created <code>Buffer</code> will\nshare the same allocated memory as the <a href=\"https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray\"><code>TypedArray</code></a>.</p>\n<p>The optional <code>byteOffset</code> and <code>length</code> arguments specify a memory range within\nthe <code>arrayBuffer</code> that will be shared by the <code>Buffer</code>.</p>\n<pre><code class=\"lang-js\">const arr = new Uint16Array(2);\n\narr[0] = 5000;\narr[1] = 4000;\n\n// Shares memory with `arr`\nconst buf = new Buffer(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>\n</code></pre>\n"
},
{
"params": [
{
"textRaw": "`buffer` {Buffer} An existing `Buffer` to copy data from. ",
"name": "buffer",
"type": "Buffer",
"desc": "An existing `Buffer` to copy data from."
}
],
"desc": "<p>Copies the passed <code>buffer</code> data onto a new <code>Buffer</code> instance.</p>\n<pre><code class=\"lang-js\">const buf1 = new Buffer('buffer');\nconst buf2 = new Buffer(buf1);\n\nbuf1[0] = 0x61;\n\nconsole.log(buf1.toString());\n// Prints: auffer\nconsole.log(buf2.toString());\n// Prints: buffer\n</code></pre>\n"
},
{
"params": [
{
"name": "buffer"
}
],
"desc": "<p>Copies the passed <code>buffer</code> data onto a new <code>Buffer</code> instance.</p>\n<pre><code class=\"lang-js\">const buf1 = new Buffer('buffer');\nconst buf2 = new Buffer(buf1);\n\nbuf1[0] = 0x61;\n\nconsole.log(buf1.toString());\n// Prints: auffer\nconsole.log(buf2.toString());\n// Prints: buffer\n</code></pre>\n"
},
{
"params": [
{
"textRaw": "`size` {integer} The desired length of the new `Buffer`. ",
"name": "size",
"type": "integer",
"desc": "The desired length of the new `Buffer`."
}
],
"desc": "<p>Stability: 0 - Deprecated: Use <a href=\"#buffer_class_method_buffer_alloc_size_fill_encoding\"><code>Buffer.alloc()</code></a> instead (also see\n<a href=\"#buffer_class_method_buffer_allocunsafe_size\"><code>Buffer.allocUnsafe()</code></a>).</p>\n<p>Allocates a new <code>Buffer</code> of <code>size</code> bytes. If the <code>size</code> is larger than\n<a href=\"#buffer_buffer_constants_max_length\"><code>buffer.constants.MAX_LENGTH</code></a> or smaller than 0, a <a href=\"errors.html#errors_class_rangeerror\"><code>RangeError</code></a> will be\nthrown. A zero-length <code>Buffer</code> will be created if <code>size</code> is 0.</p>\n<p>Prior to Node.js 8.0.0, the underlying memory for <code>Buffer</code> instances\ncreated in this way is <em>not initialized</em>. The contents of a newly created\n<code>Buffer</code> are unknown and <em>may contain sensitive data</em>. Use\n<a href=\"#buffer_class_method_buffer_alloc_size_fill_encoding\"><code>Buffer.alloc(size)</code></a> instead to initialize a <code>Buffer</code>\nwith zeroes.</p>\n<pre><code class=\"lang-js\">const buf = new Buffer(10);\n\nconsole.log(buf);\n// Prints: <Buffer 00 00 00 00 00 00 00 00 00 00>\n</code></pre>\n"
},
{
"params": [
{
"name": "size"
}
],
"desc": "<p>Stability: 0 - Deprecated: Use <a href=\"#buffer_class_method_buffer_alloc_size_fill_encoding\"><code>Buffer.alloc()</code></a> instead (also see\n<a href=\"#buffer_class_method_buffer_allocunsafe_size\"><code>Buffer.allocUnsafe()</code></a>).</p>\n<p>Allocates a new <code>Buffer</code> of <code>size</code> bytes. If the <code>size</code> is larger than\n<a href=\"#buffer_buffer_constants_max_length\"><code>buffer.constants.MAX_LENGTH</code></a> or smaller than 0, a <a href=\"errors.html#errors_class_rangeerror\"><code>RangeError</code></a> will be\nthrown. A zero-length <code>Buffer</code> will be created if <code>size</code> is 0.</p>\n<p>Prior to Node.js 8.0.0, the underlying memory for <code>Buffer</code> instances\ncreated in this way is <em>not initialized</em>. The contents of a newly created\n<code>Buffer</code> are unknown and <em>may contain sensitive data</em>. Use\n<a href=\"#buffer_class_method_buffer_alloc_size_fill_encoding\"><code>Buffer.alloc(size)</code></a> instead to initialize a <code>Buffer</code>\nwith zeroes.</p>\n<pre><code class=\"lang-js\">const buf = new Buffer(10);\n\nconsole.log(buf);\n// Prints: <Buffer 00 00 00 00 00 00 00 00 00 00>\n</code></pre>\n"
},
{
"params": [
{
"textRaw": "`string` {string} String to encode. ",
"name": "string",
"type": "string",
"desc": "String to encode."
},
{
"textRaw": "`encoding` {string} The encoding of `string`. **Default:** `'utf8'` ",
"name": "encoding",
"type": "string",
"desc": "The encoding of `string`. **Default:** `'utf8'`",
"optional": true
}
],
"desc": "<p>Stability: 0 - Deprecated:\nUse <a href=\"#buffer_class_method_buffer_from_string_encoding\"><code>Buffer.from(string[, encoding])</code></a> instead.</p>\n<p>Creates a new <code>Buffer</code> containing <code>string</code>. The <code>encoding</code> parameter identifies\nthe character encoding of <code>string</code>.</p>\n<pre><code class=\"lang-js\">const buf1 = new Buffer('this is a tést');\nconst buf2 = new Buffer('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('ascii'));\n// Prints: this is a tC)st\n</code></pre>\n"
},
{
"params": [
{
"name": "string"
},
{
"name": "encoding",
"optional": true
}
],
"desc": "<p>Stability: 0 - Deprecated:\nUse <a href=\"#buffer_class_method_buffer_from_string_encoding\"><code>Buffer.from(string[, encoding])</code></a> instead.</p>\n<p>Creates a new <code>Buffer</code> containing <code>string</code>. The <code>encoding</code> parameter identifies\nthe character encoding of <code>string</code>.</p>\n<pre><code class=\"lang-js\">const buf1 = new Buffer('this is a tést');\nconst buf2 = new Buffer('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('ascii'));\n// Prints: this is a tC)st\n</code></pre>\n"
}
]
},
{
"textRaw": "Class: SlowBuffer",
"type": "class",
"name": "SlowBuffer",
"meta": {
"deprecated": [
"v6.0.0"
],
"changes": []
},
"stability": 0,
"stabilityText": "Deprecated: Use [`Buffer.allocUnsafeSlow()`] instead.",
"desc": "<p>Returns an un-pooled <code>Buffer</code>.</p>\n<p>In order to avoid the garbage collection overhead of creating many individually\nallocated <code>Buffer</code> instances, by default allocations under 4KB are sliced from a\nsingle larger allocated object.</p>\n<p>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 <code>Buffer</code> instance using <code>SlowBuffer</code> then copy out the relevant bits.</p>\n<pre><code class=\"lang-js\">// Need to keep around a few small chunks of memory\nconst store = [];\n\nsocket.on('readable', () => {\n const data = socket.read();\n\n // Allocate for retained data\n const sb = SlowBuffer(10);\n\n // Copy the data into the new allocation\n data.copy(sb, 0, 0, 10);\n\n store.push(sb);\n});\n</code></pre>\n<p>Use of <code>SlowBuffer</code> should be used only as a last resort <em>after</em> a developer\nhas observed undue memory retention in their applications.</p>\n",
"signatures": [
{
"params": [
{
"textRaw": "`size` {integer} The desired length of the new `SlowBuffer`. ",
"name": "size",
"type": "integer",
"desc": "The desired length of the new `SlowBuffer`."
}
],
"desc": "<p>Allocates a new <code>Buffer</code> of <code>size</code> bytes. If the <code>size</code> is larger than\n<a href=\"#buffer_buffer_constants_max_length\"><code>buffer.constants.MAX_LENGTH</code></a> or smaller than 0, a <a href=\"errors.html#errors_class_rangeerror\"><code>RangeError</code></a> will be\nthrown. A zero-length <code>Buffer</code> will be created if <code>size</code> is 0.</p>\n<p>The underlying memory for <code>SlowBuffer</code> instances is <em>not initialized</em>. The\ncontents of a newly created <code>SlowBuffer</code> are unknown and may contain sensitive\ndata. Use <a href=\"#buffer_buf_fill_value_offset_end_encoding\"><code>buf.fill(0)</code></a> to initialize a <code>SlowBuffer</code> with\nzeroes.</p>\n<pre><code class=\"lang-js\">const { SlowBuffer } = require('buffer');\n\nconst buf = new SlowBuffer(5);\n\nconsole.log(buf);\n// Prints: (contents may vary): <Buffer 78 e0 82 02 01>\n\nbuf.fill(0);\n\nconsole.log(buf);\n// Prints: <Buffer 00 00 00 00 00>\n</code></pre>\n"
},
{
"params": [
{
"name": "size"
}
],
"desc": "<p>Allocates a new <code>Buffer</code> of <code>size</code> bytes. If the <code>size</code> is larger than\n<a href=\"#buffer_buffer_constants_max_length\"><code>buffer.constants.MAX_LENGTH</code></a> or smaller than 0, a <a href=\"errors.html#errors_class_rangeerror\"><code>RangeError</code></a> will be\nthrown. A zero-length <code>Buffer</code> will be created if <code>size</code> is 0.</p>\n<p>The underlying memory for <code>SlowBuffer</code> instances is <em>not initialized</em>. The\ncontents of a newly created <code>SlowBuffer</code> are unknown and may contain sensitive\ndata. Use <a href=\"#buffer_buf_fill_value_offset_end_encoding\"><code>buf.fill(0)</code></a> to initialize a <code>SlowBuffer</code> with\nzeroes.</p>\n<pre><code class=\"lang-js\">const { SlowBuffer } = require('buffer');\n\nconst buf = new SlowBuffer(5);\n\nconsole.log(buf);\n// Prints: (contents may vary): <Buffer 78 e0 82 02 01>\n\nbuf.fill(0);\n\nconsole.log(buf);\n// Prints: <Buffer 00 00 00 00 00>\n</code></pre>\n"
}
]
}
],
"properties": [
{
"textRaw": "`INSPECT_MAX_BYTES` {integer} **Default:** `50` ",
"type": "integer",
"name": "INSPECT_MAX_BYTES",
"meta": {
"added": [
"v0.5.4"
],
"changes": []
},
"desc": "<p>Returns the maximum number of bytes that will be returned when\n<code>buf.inspect()</code> is called. This can be overridden by user modules. See\n<a href=\"util.html#util_util_inspect_object_options\"><code>util.inspect()</code></a> for more details on <code>buf.inspect()</code> behavior.</p>\n<p>Note that this is a property on the <code>buffer</code> module returned by\n<code>require('buffer')</code>, not on the <code>Buffer</code> global or a <code>Buffer</code> instance.</p>\n",
"shortDesc": "**Default:** `50`"
},
{
"textRaw": "`kMaxLength` {integer} The largest size allowed for a single `Buffer` instance. ",
"type": "integer",
"name": "kMaxLength",
"meta": {
"added": [
"v3.0.0"
],
"changes": []
},
"desc": "<p>An alias for <a href=\"#buffer_buffer_constants_max_length\"><code>buffer.constants.MAX_LENGTH</code></a></p>\n<p>Note that this is a property on the <code>buffer</code> module returned by\n<code>require('buffer')</code>, not on the <code>Buffer</code> global or a <code>Buffer</code> instance.</p>\n",
"shortDesc": "The largest size allowed for a single `Buffer` instance."
}
],
"methods": [
{
"textRaw": "buffer.transcode(source, fromEnc, toEnc)",
"type": "method",
"name": "transcode",
"meta": {
"added": [
"v7.1.0"
],
"changes": [
{
"version": "v8.0.0",
"pr-url": "https://github.com/nodejs/node/pull/10236",
"description": "The `source` parameter can now be a `Uint8Array`."
}
]
},
"signatures": [
{
"params": [
{
"textRaw": "`source` {Buffer|Uint8Array} A `Buffer` or `Uint8Array` instance. ",
"name": "source",
"type": "Buffer|Uint8Array",
"desc": "A `Buffer` or `Uint8Array` instance."
},
{
"textRaw": "`fromEnc` {string} The current encoding. ",
"name": "fromEnc",
"type": "string",
"desc": "The current encoding."
},
{
"textRaw": "`toEnc` {string} To target encoding. ",
"name": "toEnc",
"type": "string",
"desc": "To target encoding."
}
]
},
{
"params": [
{
"name": "source"
},
{
"name": "fromEnc"
},
{
"name": "toEnc"
}
]
}
],
"desc": "<p>Re-encodes the given <code>Buffer</code> or <code>Uint8Array</code> instance from one character\nencoding to another. Returns a new <code>Buffer</code> instance.</p>\n<p>Throws if the <code>fromEnc</code> or <code>toEnc</code> specify invalid character encodings or if\nconversion from <code>fromEnc</code> to <code>toEnc</code> is not permitted.</p>\n<p>The transcoding process will use substitution characters if a given byte\nsequence cannot be adequately represented in the target encoding. For instance:</p>\n<pre><code class=\"lang-js\">const buffer = require('buffer');\n\nconst newBuf = buffer.transcode(Buffer.from('€'), 'utf8', 'ascii');\nconsole.log(newBuf.toString('ascii'));\n// Prints: '?'\n</code></pre>\n<p>Because the Euro (<code>€</code>) sign is not representable in US-ASCII, it is replaced\nwith <code>?</code> in the transcoded <code>Buffer</code>.</p>\n<p>Note that this is a property on the <code>buffer</code> module returned by\n<code>require('buffer')</code>, not on the <code>Buffer</code> global or a <code>Buffer</code> instance.</p>\n"
}
],
"type": "module",
"displayName": "Buffer"
}
]
}