[RyanCavanaugh]

Flow doesn't even check that array access is in-bounds, contrast to TypeScript with noUncheckedIndexedAccess on. They're clearly equally willing to make a few trade-offs for developer convenience (a position I entirely agree with FWIW)

[price]

Neat example, thanks! I hadn't known TS had that option. Array access was actually exactly the example that came to mind for me in a related discussion: https://news.ycombinator.com/item?id=41076755

I wonder how widely used that option is. As I said in that other comment, it feels to me like the sort of thing that would produce errors all over the place, and would therefore be a real pain to migrate to. (It'd be just fine if the language semantics were that out-of-bounds array access throws, but that's not the semantics JS has.) I don't have a real empirical sense of that, though.