【Node】【Buffer】

buffer 对数据进行转换

const buf = Buffer.from('123ABCabc', 'ascii');
console.log(buf.toString('hex'));


const buf2 = Buffer.alloc(10, 1);
console.log(buf2);

// 创建一个包含 [0x1, 0x2, 0x3] 的 Buffer。
const buf4 = Buffer.from([1, 2, 3]);



const buf5 = Buffer.from('今天是个好天气');
console.log(buf5.toString('utf8'));

//写入字节数
buf = Buffer.alloc(256);
len = buf.write("www.runoob.com");

console.log("写入字节数 : "+  len);

buf = Buffer.alloc(26);
for (var i = 0 ; i < 26 ; i++) {
  buf[i] = i + 97;
}

console.log( buf.toString('ascii'));       // 输出: abcdefghijklmnopqrstuvwxyz
console.log( buf.toString('ascii',0,5));   // 输出: abcde
console.log( buf.toString('utf8',0,5));    // 输出: abcde
console.log( buf.toString(undefined,0,5)); // 使用 'utf8' 编码, 并输出: abcde



var buf = Buffer.from('www.runoob.com');
var json = buf.toJSON(buf);

console.log(json);


var buffer1 = Buffer.from(('菜鸟教程'));
var buffer2 = Buffer.from(('www.runoob.com'));
var buffer3 = Buffer.concat([buffer1,buffer2]);
console.log("buffer3 内容: " + buffer3.toString());