Buffer、ArrayBuffer及DataView之间的转换

Buffer

　　是Nodejs提供的可以直接操作二进制数据的类

ArrayBuffer

　　是符合ES标准的

　　用来表示通用的、固定长度的原始二进制数据缓冲区，是一个字节数组，可读但不可直接写

注：

　　ArrayBuffer对象并没有提供任何读写内存的方法，但允许在其上方建立DataView，从而插入与读取内存中的数据

DataView 

　　是一个可以从 ArrayBuffer 对象中读写多种数值类型的底层接口

　　类型有

Int8Array：8位有符号整数，长度1个字节
Uint8Array：8位无符号整数，长度1个字节
Int16Array：16位有符号整数，长度2个字节
Uint16Array：16位无符号整数，长度2个字节
Int32Array：32位有符号整数，长度4个字节
Uint32Array：32位无符号整数，长度4个字节
Float32Array：32位浮点数，长度4个字节
Float64Array：64位浮点数，长度8个字节

1.buffer 转 Uint8Array

var buffer = Buffer.from('hello,world');
var arraybuffer = new Uint8Array(buffer);
console.log(arraybuffer);

Uint8Array(11) [
104, 101, 108, 108,
111, 44, 119, 111,
114, 108, 100
]

2.Uint8Array 转 ArrayBuffer

var buffer = Buffer.from('hello,world');
var array = new Uint8Array(buffer);
var arraybuffer = array.buffer;
console.log(arraybuffer);

ArrayBuffer {
[Uint8Contents]: <68 65 6c 6c 6f 2c 77 6f 72 6c 64>,
byteLength: 11
}

3. ArrayBuffer转 Buffer

var buffer = Buffer.from('hello,world');
var array = new Uint8Array(buffer);
var arraybuffer = array.buffer;
var buffer1 = Buffer.from(arraybuffer);
console.log(buffer1);

<Buffer 68 65 6c 6c 6f 2c 77 6f 72 6c 64>

4.ArrayBuffer转 DataView 

var buffer = Buffer.from('hello,world');
var array = new Uint8Array(buffer);
var arraybuffer = array.buffer;
var view = new DataView(arraybuffer);
console.log(view);

5.DataView转ArrrayBuffer

var buffer = Buffer.from('hello,world');
var array = new Uint8Array(buffer);
var arraybuffer = array.buffer;
var view = new DataView(arraybuffer);
var buffer1 = view.buffer;
console.log(buffer1);

ArrayBuffer {
[Uint8Contents]: <68 65 6c 6c 6f 2c 77 6f 72 6c 64>,
byteLength: 11
}