I wish people would stop saying "JavaScript was written in 10 days" with the subtle implication that this is somehow shoddy or half-arsed. GvR wrote the first version of Python in a month in December 1989; the first bit of C was made out of B and NB in a month or two in ~1970. Every single bit of software you've ever used that isn't some enterprise nightmare was first a proof of concept hacked together in a couple of weeks by whoever first did it. This is entirely normal; it's not a bad thing!
@sil My parents said my MVP took about 4½ minutes.
Then a couple decades of minor and major revs