In today’s tutorial, we’re going to learn how to declare, interact, and scope variables in JavaScript. We’ll introduce new concepts and important JavaScript keywords like var, let and const.

If you write JavaScript, you have probably used higher-order functions and not even noticed. If you have ever replaced a for loop with an array method, you’ve used higher-order functions.

Ordinarily with JavaScript, you can change pretty much any variable you want. Any variable you declare can be reassigned to any other value, unless you use the const keyword.