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
    81·
    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)?

    • EpheraEnglish
      71·
      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…

      • DerPapa69English
        61·
        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!

    • CannotSleep420@lemmygrad.mlOP
      5·
      2 years ago

      I guess what I’m trying to say is that while Typescript is great, the types just make the development experience much nicer but don’t actually prevent any of the fuckery of Javascript. As for whether it’s strongly typed or not, I don’t find the term helpful. People call Typescript strongly typed, but is a language really strongly typed if you can tell it to ignore types? Strong is a relative term that doesn’t tell you much about the type system.

      • EpheraEnglish
        2·
        2 years ago

        Yeah, at this point, I’m basically using “strongly typed” as “How expressive/useful is the type system?”.

        Haskell, Rust, Scala, OCaml → Strongly typed.
        Python, JavaScript, C, Go → Worse than that.

        Personally, I would still put TypeScript in the strong category, because unless you are using as, it does have a helpful type system. A language preventing shitfuckery during runtime is kind of too late anyways.

        But yeah, sometimes even the best type system cannot express everything you know to be true as a human. Then you need to start casting. But casting can break during refactoring, so a language at least telling you during runtime that the cast is broken, is more helpful than a language just accepting shitfuckery. So, this does make TypeScript somewhat less strongly typed, even with my definition.