Hacker News new | ask | show | jobs
by eyelidlessness 1197 days ago
What is the distinction?
1 comments

The distinction is just because you "don't care" about the values right now, nothing stops the next developer (including future you) from needing the values.

So now you've gone from not caring to "enabling someone to shoot themselves in the foot" if they don't read the types of the parameters carefully. That's the difference.

The case I was trying to convey doesn’t narrow the actual type for anything outside its own function body. Any footgun that exists after the function call already existed before it. It just implies “I’m only looking at your keys not your values”.
> It just implies “I’m only looking at your keys not your values”.

That's what `unknown` is for. `any` behaves like `never` (in covariant positions), which is exactly the opposite.

I don’t think that’s how `any` behaves in any position, but I’d be happy to be corrected. Please show me how `any` is treated as `never`.
Here's a close to minimal example:

    const anyToNeverHelper = <T,>(t: any): number & T => t
    const absurd: never = anyToNeverHelper<never>(0)
This is a good example of how `never` is treated as `never`. Everything is assignable to the bottom type and intersecting with it will always be the bottom type, by definition. It’s also a good example of how the top type `any` casts to whatever you choose, because that’s also by design. Both types are vacant, the bottom type is infectious. That’s a good thing. And it works the same way with `unknown`, which it also should because once something is known to be part of the null set it should stay known as the null set.
I gathered what you meant. My point is what stops the next developer working on your codebase from adding code in the body of your function that accesses the values of the object in an unsafe way?
A bit of trust. I’m not aware of a type system that protects my coworkers from my bad decisions, only those humans do that.