Trying to understand recursion within for loops in javascript

Question

I\'ve been staring at the answer to this question forever even writing down variables and whatnot through each iteration. I simply just don\'t get the process here. When I

Answer 1

The code is a bit hard to follow, because it's a mix of looping and recursion. It uses a global variable (usedChars) that is changed and restored during each call.

"each time permute is called, it is a new instance of that function with it's own closure right? therefore variables changes that are within the function won't affect variables in other calls?"

Well, yes and no. Each function call has its own scope, but as there are no variables that needs catching, there is no closure. The local variables i and ch and the parameter input are local to the scope, so each call has their own set of those variables. Any other variables are global, so they are shared between all calls.

The variable usedChars is changed in the code, and that change is visible to the code when the function does the recursive call, and then the variable is changed back to the previous state for the next iteration. When the function exists, the variable has the value that it had when the function was entered.

"does the function return permArr for each time it's called?"

Yes, but when the function calls itself, the return value is ignored. It's only when the array is returned from the outermost call that it is used.