ES6 support in Lightning Components

Lightning Components do not fully support ES6 syntax. However, a few important functions, such as Promise and array utilities, such as filter, map, and reduce functions, have been found to work, as of the current version.

An introduction to Promises

If you never need the capability to nest callbacks, your code can become difficult to debug and maintain. The following code snippet shows an example of nested callbacks (they are also commonly referred to as callback hell):

getUsers(function () {
    getUserDetail(function () {
        getProductsPurchasedByUser(function() {
            getRecommendedProducts(function () {

            });
        });
    });
});

The Promise API (https://developer.mozilla.Org/en-US/docs/Web/JavaScript/Guide/Using_promises) in JavaScript solves the problem of callback hell by returning the object that can attach callbacks, rather than passing the callback a the parameter.

The preceding code snippet for a nested callback can be written...