es6 arrow functions and es5 functions comparison

es5 functions

var fs = require("fs");

function add(x, y) {
	return x + y;
}

var nums = [1,2,3,4,5];
var newNums = nums.map(function(n){return n*2});

console.log(add(3,10));
console.log(nums, newNums);
fs.readFile("./arrow_functions.js", "utf-8", function (err, data) {
	if (err) console.log(err);
	console.log(data);
});

Equivalent functions written in es6 with arrow notation. It’s basically replacing the keyword function with the arrow =>

let fs = require("fs");

let add  = (x, y) => {return x + y;}
let nums = [1,2,3,4,5];
let newNums = nums.map(
	(n) => {return n*2}
	);

console.log(add(3,10));
console.log(nums, newNums);


fs.readFile("./arrow_functions.js", "utf-8", (err, data) => {
	if (err) console.log(err);
	console.log(data);
});