arg: keyof T and T[arg] is a number

[night hare]

I have a class that takes a generic T. I want to guarantee that the argument objectKey is a key of the object that conforms to T, and that T[objectKey] is a number.

class MyClass<T> {
  constructor(public objectKey: keyof T) {}
}

[unkempt wave]

perhaps something like this?
class MyClass<K extends PropertyKey, T extends Record<K, number>>
then use K

weird pattern though, why do you need something like this

[night hare]

It's a priority queue-like class that automatically sorts items on a given property key. I'm just trying to make that key able to be checked at compile time.

[unkempt wave]

why enforce that it's a number then? i feel you could also do sorting by Date or string or whatever

[night hare]

Is there a way I could avoid having to pass in an additional type argument? Currently, this solution seems to break existing usage of the class.

[unkempt wave]

in that case i feel you could get more mileage by providing a sorting callback, like how sort works

[night hare]

It's used specifically in pathfinding, for keeping track of nodes to visit. The sort key is almost always the total distance from the first node to that node

[unkempt wave]

not that i know of, sorry

[night hare]

Again, this isn't really ideal since it breaks exisiting usage

[unkempt wave]

why have it be generic at all then?

[night hare]

Oh well, thanks for trying - you did better that I managed

[night hare]

It's used slightly differently with different node classes in different places

[unkempt wave]

do those node classes have other properties that you're sorting by?

[night hare]

yeah, the naming varies

I guess I could have an union somwhere of all the different keys, but that just feels like way overcompilcating

[unkempt wave]

i feel sort-like callbacks are the way to go there

[unkempt wave]

yeah that's definitely overcomplicating it

[night hare]

You're right, but again - just trying to tidy up some types here and there, not refactor the actual functional parts of working code