I would use two mutually recursive functions rather than a single recursive function, as it’s possible for an implementor to implement TCE for recursive functio

I would use two mutually recursive functions rather than a single recursive function, as it’s possible for an implementor to implement TCE for recursive functions, but not for the general case. I’d also up the number. That code runs fine in Safari for 20,000, I had to use 200,000 to get it to break.