Promise -fication of JS calls.

Found a new pattern to use recently that is called Promise. I really like the way ES6/7 brings new thinking patterns into life nowdays. Here is Promise used instead of old pattern.

It was to give JS method a callback function. This splitting code and making a lot of possibilities for error to come out in this place.

One would write old times according to MDN:
function greeting(name) {
  alert('Hello ' + name);
}

function processUserInput(callback) {
  var name = prompt('Please enter your name.');
  callback(name);
}

processUserInput(greeting);
And now it is made with Promise pattern like so:
let promise = new Promise((resolve, reject) => {
  resolve(prompt('Please enter your name.'));
});

promise.then((name) => { 
    alert('Hello ' + name); 
});
In general and briefly this now helps to avoid 'callback hell' with functions passed as arguments and write asynchronous code a sort of in synchronous manner.

This all becomes extra useful upon one having need to load set of data from a different sources. E.g. via several API cals to different url's and react accordingly.

Hail to ES6!

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