type-challenges-solutions/en/medium-objectentries

[utterances-bot]

ObjectEntries

This project is aimed at helping you better understand how the type system works, writing your own utilities, or just having fun with the challenges.

https://ghaiklor.github.io/type-challenges-solutions/en/medium-objectentries.html

[zhaoyao91]

This doesn't work for such cases

Expect<Equal<ObjectEntries<{ key: 1 | undefined }>, ['key', 1 | undefined]>>,
Expect<Equal<ObjectEntries<{ key?: 1 | undefined }>, ['key', 1 | undefined]>>,

[ghaiklor]

@zhaoyao91 did you manage to improve the solution to get those tests passing?

[zhaoyao91]

@ghaiklor sadlly, I didn't find a perfect solution yet. Naive solution would indeed pass most cases but the Partial<Model> one. see type-challenges/type-challenges#19507

[albert-luta]

This is my solution so far

type ObjectEntries<
  T extends Record<keyof any, any>,
  K extends keyof T = keyof T
> = K extends any
  ? [K, Required<T>[K] extends never ? undefined : Required<T>[K]]
  : never;

[JanessaTech]

Here is my solution: all test cases passed:

type ObjectEntries<M, T = Required<M>> = {
      [P in keyof T]-?: [P, T[P] extends never ?  undefined : T[P]]
  }[keyof T]

[JanessaTech]

Update:
no need -?:

type ObjectEntries<M, T = Required<M>> = {
      [P in keyof T]: [P, T[P] extends never ?  undefined : T[P]]
  }[keyof T]