My very minor complaint about TypeScript is you use to use `const` which is 2 additional letters.

Seriously though, I do find it slightly difficult to reason about `const` vars in TypeScript because while a `const` variable cannot be reassigned, the value it references can still be mutated. I think TypeScript would benefit from more non-mutable values types... (I know there are some)

Swift has the same problem, in theory, but it's very easy to use a non-mutable value types in Swift (`struct`) so it's mitigated a bit.