devto-1-promise-example.js

//  The method wich return a promise
function thePromiseGiver() {
  return new Promise((resolve, reject) => {
    let dice = Math.floor(Math.random() * Math.floor(6));
    if (dice>=3) {
      resolve(dice);
    }else{
      reject(new Error(dice));
    }
  }); 
}

//  What to do if everythings right
function yes () {
  console.log("Yes, I'll do it !");
}

//  What to do if we have a bad thing
function no () {
  console.error("Nope, drop it !");
}

//  Execute the first method and THEN call the next one according to the result
thePromiseGiver().then(yes,no);