fractal-tree | Fractal tree | Animation library

Excellent work!

I'd like some help on the portion of the code that needs to be changed to turn this function into an iterative function.

I identify three parts of your code:

1. The part that generates an SVG string
2. The part that interacts with files
3. The part that calls itself recursively

I would separate those parts so that you can compose them any way you like without depending deeply on the other. For example so that you can compose fractal effects without necessarily composing filesystem effects.

As for iteration vs. recursion, since you're in a functional language, I would recommend to continue with recursion. But because your recursive pattern is tree-shaped (every call potentially creates two other calls), your recursion risks overflowing heap memory.

So an iterative solution and a tail-recursive solution would achieve the same thing: Since you recurse both left and right, but not at the same time, you can explicitly rather than implicitly store, using a stack, that you're recursing the other way later, too.

Here is a rewrite; I'll comment below: