promise1.js

function random(){
  return Math.floor(Math.random() * 10);
}

function getJSON() {
  return new Promise(function (resolve, reject) {
    setTimeout(() => resolve('Yes'),random());
    setTimeout(() => reject('No'), random());
  }); 
}

var promise = getJSON()
  .then((data) => {
    console.log(data);
  }).catch((data) => {
    console.log(data);
  });