Theo's Typesafe Cult•2y ago

Objects of objects of a certain type

I am trying to create an object whose keys can be anything, but values are of a certain type. Each object is essentially a link, that has a certain shape. Then I put them in a wrapper object like this, however each object within is typed indivdually instead of the overall object. The problem is when I try and loop over the wrapper object LINKS, it is not giving me typesaftey. How do i fix this?

17 Replies

erik.gh•2y ago

type Links = {
  [K: string]: LinkProperties
}

type Links = {
  [K: string]: LinkProperties
}

like this?

GeorgeOP•2y ago

thankyou, but when i tried this, there is no autocomplete when you do LINKS.

erik.gh•2y ago

oh then you might just want to use what you already had and add as const to the LINKS object

GeorgeOP•2y ago

i agree, but the wrapper object still isnt typed as containing only LinkProperties

GeorgeOP•2y ago

or maybe ts doesnt allow doing that in general, im not sure, im very new to ts

erik.gh•2y ago

yeah i understand not sure how to solve it tho

GeorgeOP•2y ago

all good, thanks for you help anyway

awexis•2y ago

maybe satisfies: but its more like what you had here. https://tsplay.dev/wOLy7N

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GeorgeOP•2y ago

i agree, thanks for the help

whatplan•2y ago

just wanted to add that the Record type does the same thing as this but tiny bit shorter

type LinksType =  Record<string, LinkProperties>

type LinksType =  Record<string, LinkProperties>

doesnt change all that much but cool to know

erik.gh•2y ago

yeah right thank you but consting an object with dynamic keys is not a thing?

whatplan•2y ago

const LINKS = {
  dashboard,
  patients
}

type LinksType =  Record<keyof typeof LINKS, LinkProperties>

const LINKS = {
  dashboard,
  patients
}

type LinksType =  Record<keyof typeof LINKS, LinkProperties>

whatplan•2y ago

hovering LinksType

whatplan•2y ago

in this case LinksTypes possible keys are defined by the keys of some object you have to define the type somewhere either it can be super generic (Record<string, LinkProperties>) or super specific (as const) but the whole point of a type is to know what your getting in advance so if the type is super dynamic then you might have some challenges getting the level of autocomplete you are hoping for

whatplan•2y ago

A type cant refer to itself

whatplan•2y ago

So somewhere you have to tell typescript every possible value for a key in your object If you cant describe that as a list of specific things (either by actually writing it out, or by referencing another type) the best you can do is just string (or whatever type your using to index)

erik.gh•2y ago

that makes sense the type would have to change as you only want to type the values first and later infer the keys which is not a thing in ts

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Objects of objects of a certain type