' node. js ' buffer (buffer)

In node. js, a buffer class is defined that is used to create a buffer that is dedicated to storing the binary data.

Create a Buffer class

The Node Buffer class can be created in several ways.

1. Create a Buffer instance with a length of 10 bytes:

var New Buffer (10);

2. Create a Buffer instance from the given array:

var New Buffer ([10, 20, 30, 40, 50]);

3. Create a Buffer instance with a string:

var New Buffer ("www.runoob.com", "utf-8");

Utf-8 is the default encoding method, and it also supports the following encodings: "ASCII", "UTF8", "Utf16le", "UCS2", "base64" and "hex".

Write buffers

The syntax for writing to the Node buffer is as follows:

Buf.write (string[, offset[, length]][, encoding])

Returns the actual write size. If the buffer space is insufficient, only a partial string is written.

New Buffer (= Buf.write ("www.runoob.com"); Console.log ("bytes written:" +  len);

Reading data from a buffer

The syntax for reading the Node buffer data is as follows:

Buf.tostring ([encoding[, start[, end]])

Decodes the buffer data and returns a string using the specified encoding.

New Buffer (+);  for (var i = 0; i <; i++) {  = i + +;} Console.log (buf.tostring (' ASCII '));       // output: abcdefghijklmnopqrstuvwxyzconsole.log (buf.tostring (' ASCII ', 0,5));   // output: ABCDEconsole.log (buf.tostring (' UTF8 ', 0,5));    // Output: ABCDE // use ' UTF8 ' encoding, and output: ABCDE

Convert Buffer to JSON object

Buf.tojson ()

Buffer Merge

Buffer.concat (list[, Totallength])

Buffer comparison

Buf.compare (Otherbuffer);

Copy buffer

Buf.copy (targetbuffer[, targetstart[, sourcestart[, Sourceend]])

Buffer clipping

Buf.slice ([start[, end]])

Buffer length

Buf.length;

' node. js ' buffer (buffer)