class Lol {
    get length() {
        console.log('Lol. LMAO even.');
        return 5;
    }
}

const noLolsAllowed = (notALol: string) => {
    for (let i = 0; i < notALol.length; ++i) {
        console.log('No lols here');
    }
}

noLolsAllowed(new Lol() as unknown as string);
  • DerPapa69@lemmy.ml
    3·
    2 years ago

    I don’t really get the point of this. Of course the function will accept the value as a string if you specifically tell it to treat it as such (which wouldn’t even be possible without casting it to unknown first)?

    • Ephera@lemmy.mlEnglish
      4·
      2 years ago

      I guess the point is, it’s not strongly typed during runtime. In other strongly typed languages, that cast would fail, since the underlying memory layout of some random class does not fit to that of a string.

      But yeah, as soon as you break out as, you’re telling the type system to fuck off. So, while it does look freaky to me, too, it doesn’t dispell that TypeScript is strongly typed…

      • DerPapa69@lemmy.mlEnglish
        2·
        2 years ago

        Yeah, I do agree that it’s a bit weird with TS. It’s fully understandable though, since it just transpiles to JS, which doesn’t have any type information during runtime. I think as far as webdev goes though, TS makes it at least somewhat bearable.

        Sorry for the downvote btw - that wasn’t me!