Arrow functions are a really handy new part of the ES6 JavaScript spec.

Along with shorter, more concise syntax one of the benefits is that is handles the keyword this a little differently. More specifically, it doesn't change the binding of this when you enter into a new function that was declared with an arrow.

So, while you'll use this in any of your JavaScript, here is a problem we have all run into with jQuery events, and how you can fix it with ES6 arrow functions.

    // Go from this code:
    $('.cta').on('click',function() {
      var that = this;
      setTimeout(function() {
        $(that).toggleClass('on');
      }, 1000)
    });

    // To this code:
    $('.cta').on('click',function() {
      setTimeout(()=> {
        $(this).toggleClass('on');
      }, 1000)
    });