Inner functions having access to outer function's variables is called a closure. 

A Closure has three scope-chains, it has access to: 

1. Its own scope
2. The outer function's variables
3. Global variables

A simple definition of Recursion is calling a function on itself. 

Recursion follows the divide-and-conquer method, where the problem is divided into
​sub-problems, solving the sub-problems and combining them with the final result.

Structure of a recursive function includes one or more base cases and recursive cases.
Base Case:  Inputs for which the function produces the result without recurring.
Recursive Case: Inputs for which the program calls itself.

Familiarize yourself with CLI commands. Can't stress this enough, these are very helpful and you'll be using it on a day-to-day basis. I'm in love with these commands, definitely a productivity booster. 

Interested to learn more on CLI? You can find it here.

I'll be documenting everything related to Javascript. From Basic Javascript to frameworks and everything in-between. It's going to be a fun ride!