Node.js - StringDecoder

const StringDecoder = require('string_decoder').StringDecoder;

const StringDecoder = require('string_decoder').StringDecoder;
const decoder = new StringDecoder('utf8');

const buf1 = new Buffer('this is a test');
console.log(decoder.write(buf1));//prints: this is a test

const buf2 = new Buffer('7468697320697320612074c3a97374', 'hex');
console.log(decoder.write(buf2));//prints: this is a test

const buf3 = Buffer.from([0x62,0x75,0x66,0x66,0x65,0x72]);
console.log(decoder.write(buf3));//prints: buffer