callBack vs Promise

gistfile1.txt

// https://medium.com/recraftrelic/es5-vs-es6-with-example-code-9901fa0136fc
//--- ES5 callBack
function isGreater (a, b, callBack) {
  
  var greater = false
  if(a > b) {
    greater = true
  }
  callBack(greater)
}
isGreater(1, 2, function (result) {
  if(result) {
    console.log('greater');
  } else {
    console.log('smaller')
  }
});

//--- ES6
const isGreater = (a, b) => {
 return new Promise ((resolve, reject) => {
  if(a > b) {
   resolve(true)
  } else {
   reject(false)
  }
 })
}
isGreater(1, 2)
 .then(result => {
    console.log('greater')
 })
 .catch(result => {
    console.log('smaller')
 })