Longer quote seems weird as well
> To really get the performance improvements you see, it helps dramatically to have a statically-typed language. For dynamically-typed languages, like Python, it's really, really hard. And often, what people end up doing is adding annotations to the language so that you get languages like TypeScript, which is essentially JavaScript with type annotations. And it's really funny because JavaScript is essentially Java with the type declarations removed. So TypeScript is essentially Java with permuted syntax.
He seems to be saying that TypeScript leads to faster code execution as TypeScript has types, but fails to understand that TypeScript still compiles to JS and the browsers run JS without types, so should have the same performance as just writing JS directly (probably less performance, as TSC adds bunch of wrappers and other unnecessary stuff you would avoid if writing vanilla JS)
I'm not saying this is the case, but isn't there a greater opportunity to optimize TypeScript code over JavaScript due to the presence of types? Isn't this the same thing as a statically typed program being compiled into assembly (untyped) ?
Also, C compilers generate efficient code by assuming undefined behavior cannot happen. (This sometimes corrupts buggy programs, because the type system can't guarantee undefined behavior isn't triggered.)