promise4.js

// Multiple sources with the callback pattern
getData((a) => (
  getMore(a, b => (
    andEvenMore(b, c=> (
      andLastlyMore(c, d => (
        // do something with d
      )
    )
  )
);
    
    
// same thing but now with promises
getData()
.then( (a) => getMore(a) )
.then( (b) => andEvenMore(b) )
.then( (c) => andLastlyMore(c) )
.then( (d) => /* do something with d */ )
      
      
// and lastly, the same thing but with async & await
async getMyData(){
  const a = await getdata();
  const b = await moreMore(a);  
  const c = await andEvenMore(b);
  const d = await andLastlyMore(c);
  // do somthing with d;
  // and you have access to a,b,c also.
  // and you can return d here.
  return d
}
// the async function gets returned as a promise.
getMyData.then( (d) => { /* do something with what was returned. */ } );