JavaScript Arrow Functions

A normal style function in JavaScript would look like this:

function sum(a, b) {
    return a + b;

But as this wonderful language servers everything as object, the following one is also acceptable

let sum = function(a, b) {
    return a + b;

Since programmers are lazy, the following one comes into being, which is called an arrow function

let sum = (a, b) => {return a + b;}

This is similar to lambda functions in other programming languages.