dns query use nodejs

dns.js

const print = console.log
const dns = require('dns')

const hostname = 'v2ex.com'

Promise.prototype.success = Promise.prototype.then
Promise.prototype.error = Promise.prototype.catch

function lookup(hostname) {
  return new Promise(function (resolve, reject) {
    dns.lookup(hostname, (err, address, family) => {
      if (err) {
        reject(err)
      }
      else {
        resolve(address)
      }
    })
  })
}

lookup(hostname).success(address => {
    print(`${hostname} has address: ${address}`)
}).error(e => print(e.message))