“If type checking fails then no code is generated.”
Radon Rosborough
1

“Browsers can only run JavaScript — period” is no longer correct now that WebAssembly has landed in all major browsers. Currently there are several significant limitations on what WebAssembly can do, e.g. it can’t directly access the DOM, but that just means you need a bit of JavaScript rather than 100% of it. Also, that limitation could go away in the future, in one way or another.

That doesn’t change my basic assertion that the value of TypeScript is at compile-time rather than run-time.