What is tail call recursion/optimization?
Tail Call Optimization is related to a specific type of optimization that can occur with function calls. According to Kyle Simpson, a tail call is a function call that appears at the tail of another function, such that after the call finishes, there’s nothing left to do.

Tail code optimization takes a recursive function and generate an iterative function using “goto” internally, and then execute it. It does not limit the stack calls because there are none and the function is not a recursive function more. The performance of this iterative function is equivalent to its recursive function.

In other words, tail call optimization means that it is possible to call a function from another function without growing the call stack. This is useful for large code bases.