Congratulations on finishing No Let!
So the answer is "yes". You can write JavaScript code without
using let.
After having completed all of the puzzles, you might be wondering what the point to it all was. Is pure functional programming actually useful?
Well, in my personal opinion: no. Not really. It certainly has advantages, but I don't think that they're numerous enough to outweigh the fact that functional programming simply makes it more difficult to get things done.
I didn't even write the No Let codebase using pure functional
programming. I declared dozens of let variables and mutated state
hundreds of times. Functional programming may not be all that practical, but
it's a very interesting paradigm and a lot of fun to write, as I hope you'll
agree.
I really appreciate you playing through No Let to the end. I hope you enjoyed it!
~Ethan
P.S. if you'd like to report a bug or suggest a new puzzle, feel absolutely free to open an issue on GitHub.