This should not be 7kyu. It should be more like 5.

This requires accessing the closure to get values accessible to the function in its closure scope.
This does not appear to be possible with modern JavaScript.
I spent several hours researching this and the answer that I got from any resource more recent than a year old is "this is not possible".

You shouldn't be executing any of the calls until execute is called.
Execute to evaluate the result of all the calls at once.

Is it possible to pass this with Javascript?
I wrote a recursive solution that passes all the random tests without timing out, but when I hit the performance tests I run out of stack space.
Doesn't that mean that the data is so large that there isn't enough space to finish it?
I can't think of any way to reduce the number of calls...

In ruby this kata always fails no matter what you input. I can run my algorithm on my machine and get the right answer every time. However, it always throws an error message when I enter the same code here.