Recursion: What is actually happening here?

[ArielLeslie]

I haven’t had my coffee yet, so I’m going to take shortcut and refer you to my explanation from yesterday:

Arr.push() issue in Use Recursion to Create a Range of Numbers

numbers.push(endNum) doesn’t happen until var numbers = rangeOfNumbers(startNum, endNum - 1) resolves, so we get a stack of function calls all waiting for the exit condition (endNum - startNum === 0) to be met. For example, if we start with rangeOfNumbers(1, 3) this leads to us calling rangeOfNumbers(1, 2) which calls rangeOfNumbers(1, 1). That actually returns a value ([1]), so numbers inside rangeOfNumbers(1,2) is [1] and we push to it and it returns [1, 2]. Now that rangeOfNumbers(1, 2) has…

Let me know if that doesn’t make sense and I can walk through the call stack of your function.