ES6 functions

In ES6 (Or ECMAScript 6), functions can have a slightly different look, using the "arrow functions". They are still assigned to a variable usually, in the following syntax:

const functionName = (argument, otherArugment) => {
  // function code
  return "Some Value";
}

So is there any difference between the regular and ES6 functions? There's a few, and they're all very useful.

Return is implied

If you have an arrow function that does not have curly braces, the return is implied. This means that you can greatly simplify very simple functions. For instance, our add function:

function add(arg1, arg2) {
  return arg1 + arg2;
}
// Simplified to: 
const add = (arg1, arg2) => arg1 + arg2;

This keyword is not overwritten

Mostly useful in relation to class inheritance. this , in regular functions, refers to the function itself, meaning this.thing = blah will add that property to the function or method. However, the ES6 arrow function does not overwrite this so it refers to the upper scope. This is all technobabble to some, but if you know how to work with classes and modules, you'll understand why this is useful.

Single-argument functions are simpler

When a single argument is present in an arrow function, you don't need the parentheses around that argument. Which means that const split = str => str.split(" "); is a perfectly valid function that will return an array of string parts, split by spaces (ok, not a useful function, but you get the picture).