Most importantly, this means my type system N-queens solution now works for an 8x8 chessboard (actually up to 10x10) instead of complaining about recursion depth:
They’re delivering this so quickly. 72 seconds down to 6 is a remarkable improvement, considering it’s not yet complete and assuming they haven’t spent concerted effort optimising it to perfection.
JSX checking is also big, this makes it testable on a lot of code bases