The Pick Builtin

Disclosure

Most of the problems under my TypeHero Challenges folder were either obtained from typehero.dev or from type-challenges repo. Purpose of these articles are just to document my approaches for my easy reference. Please visit the respective links for more info.

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Problem Description

Pick is a special built-in TypeScript type that’s always in scope, so you don’t need to import it from anywhere. You can just use it as-if it was already imported.

To use it, you must provide Pick with two things:

1. The type original object you’re basing your new type on (in our example, Pokemon)
2. A union of strings representing all the keys you wish to pick from the base type (in our case, name and type).

interface Pokemon {
  name: string;
  type: string;
  hitPoints: number;
  stage: string;
}
 
type BasicPokemonInfo = Pick<Pokemon, 'name' | 'type'>;

In this challenge you’ll implement the Pick type described above.

Solutions

Approach

type MyPick<T, K extends keyof T> = {
	[Key in K]: T[Key]
};