Descripcion con ejemplos de Promises y en conjunto con Async/Await

asincronia.js

//promise in a variable
let promise = new Promise(function(resolve, reject) {
  setTimeout(() => resolve("done!"), 1000);
});

// resolve runs the first function in .then
promise.then(
  result => console.log(result), // shows "done!" after 1 second
);
promise.catch(
  error => console.log(error)
)
//este codigo se ejecutara siempre primero que la promesa
console.log("primero")


//promise en una funcion
function delay(ms) {
  return new Promise( function(resolve) {
    setTimeout(function(){
      resolve('resolve inside delay after '+ ms/1000 + ' seconds' );
    }, ms)
  });
}
//Normal call to fn that returns a Promise
//delay(2000)
//  .then(data => console.log(data + ' after 2 seconds'));


//Not very clean way of call other fn after my promise is resolve
//function handlingDelayData() {
//   delay(2000).then(data => console.log('Handling: ' + data)  )  
//}

//handlingDelayData()


//Async/wait way of doit, more sync code to write
async function handlingDelayData() {
  let data =  await delay(2000);
  console.log('handling: ' + data)
}
handlingDelayData()