#Buffer
JavaScript Buffer like Node.JS buffer. Buffer class extends Uint8Array.
###new Buffer(size)
Number size
When called with a length argument, a buffer containing length zeroes is created.
TypedArray array
When called with a array argument, which can be an object of any of the typed array types (such as Int32Array), the array gets copied into a new typed array. Each value in array is converted to the corresponding type of the constructor before being copied into the new array.
String str - string to encode.
String encoding - encoding to use, Optional.
Allocates a new buffer containing the given str. encoding defaults to utf8.
Buffer obj
Return Boolean
Returns true if obj is instance of Buffer.
String str - string to encode.
String encoding - encoding to use, Optional.
Return Number
Gives the actual byte length of a string. encoding defaults to utf8. This is not the same as String.prototype.length since that returns the number of characters in a string.
Array | Buffer list - Array List of Buffer objects to concat
Number totalLength - Number Total length of the buffers when concatenated
Returns a new buffer which is the result of concatenating all the buffers in the list together.
If totalLength is not provided, it is read from the buffers in the list. However, this adds an additional loop to the function, so it is faster to provide the length explicitly.
Buffer otherBuffer
Returns a Number indicating whether this comes before or after or is the same as the otherBuffer in sort order.
If otherBuffer is not Buffer then TypeError exception is thrown.
###static Buffer.compare(buf1, buf2)
Buffer buf1
Buffer buf2
The same as Buffer.compare(otherBuffer). Useful for sorting an Array of Buffers:
If buf1 or buf2 are not Buffer then TypeError exception is thrown.
###Buffer.length
Gets the number of elements contained in the Buffer instance.
###Buffer.toString([encoding[, start[, end]]])
Decodes and returns a String from buffer data encoded using the specified character set encoding. If encoding is undefined or null, then encoding defaults to utf8. The start and end parameters default to 0 and buffer.length when undefined.
Example:
var buf = new Buffer(26);
for (var i = 0 ; i < 26 ; i++) {
buf[i] = i + 97; // 97 is ASCII a
}
buf.toString('ascii'); // outputs: abcdefghijklmnopqrstuvwxyz
buf.toString('ascii', 0, 5); // outputs: abcde
buf.toString('utf8', 0, 5); // outputs: abcde
buf.toString(undefined, 0, 5); // encoding defaults to 'utf8', outputs abcde
###Buffer.toJSON() Returns a JSON-representation of the Buffer instance. JSON.stringify implicitly calls this function when stringifying a Buffer instance.
Example:
var buf = new Buffer('test');
var json = JSON.stringify(buf);
console.log(json);
// '{"type":"Buffer","data":[116,101,115,116]}'
var copy = JSON.parse(json, function(key, value) {
return value && value.type === 'Buffer'
? new Buffer(value.data)
: value;
});
console.log(copy);
// <Buffer 116 101 115 116>
###Buffer[index]
Number index - the zero-based index of the element to get or set.
Gets or sets the element at the specified index. The values refer to individual bytes, so the legal range is between 0x00 and 0xFF hex or 0 and 255.
###Buffer.equals(otherBuffer)
Buffer otherBuffer
Returns a Boolean of whether this and otherBuffer have the same bytes.
###Buffer.slice([start[, end]])
Number start Optional, Default: 0
Number end Optional, Default: Buffer.length
Returns a new buffer sliced from the start to the end.
###Buffer.reduce(callback[, initValue])
Function callback
Function to execute on each value in the array, taking four arguments:
- previousValue The value previously returned in the last invocation of the callback, or initialValue, if supplied. (See below.)
- currentValue The current element being processed in the array.
- index The index of the current element being processed in the array.
- array The array reduce was called upon.
Variant initValue
Object to use as the first argument to the first call of the callback. Optional
Applies a function against an accumulator and each value of the array (from left-to-right) has to reduce it to a single value.
###Buffer.forEach(callback[, thisArg]) Executes a provided function once per array element.
Function callback
Function to execute for each element, taking three arguments:
- currentValue The current element being processed in the array.
- index The index of the current element being processed in the array.
- array The array reduce was called upon.
Variant thisArg
Value to use as this when executing callback. Optional
If a thisArg parameter is provided to forEach(), it will be passed to callback when invoked, for use as its this value. Otherwise, the value currentValue will be passed for use as its this value.
###Buffer.every(callback[, thisArg]) Method tests whether all elements in the array pass the test implemented by the provided function.
Function callback
Function to execute for each element, taking two arguments:
- currentValue The current element being processed in the array.
- index The index of the current element being processed in the array.
- array The array reduce was called upon.
Variant thisArg
Value to use as this when executing callback. Optional
var buf = new Buffer('test'); //Buffer [116, 101, 115, 116]
var res = buf.every(function (v,i,array) {
if (this > 200)
return true;
});
console.log(res); //false
###Buffer.some(callback[, thisArg]) Method tests whether some element in the array passes the test implemented by the provided function.
Function callback
Function to execute for each element, taking two arguments:
- currentValue The current element being processed in the array.
- index The index of the current element being processed in the array.
- array The array reduce was called upon.
Variant thisArg
Value to use as this when executing callback. Optional
Example:
var buf = new Buffer('test'); //Buffer [116, 101, 115, 116]
var res = buf.some(function (v,i,array) {
if (this < 110)
return true;
});
console.log(res); //true