02757-medium-partialbykeys.ts

// ============= Test Cases =============
import type { Equal, Expect } from "./test-utils";

interface User {
  name: string;
  age: number;
  address: string;
}

interface UserPartialName {
  name?: string;
  age: number;
  address: string;
}

interface UserPartialNameAndAge {
  name?: string;
  age?: number;
  address: string;
}

type cases = [
  Expect<Equal<PartialByKeys<User, "name">, UserPartialName>>,
  Expect<Equal<PartialByKeys<User, "name" | "age">, UserPartialNameAndAge>>,
  Expect<Equal<PartialByKeys<User>, Partial<User>>>,
  // @ts-expect-error
  Expect<Equal<PartialByKeys<User, "name" | "unknown">, UserPartialName>>
];

// ============= Your Code Here =============
type test1 = PartialByKeys<User, "name" | "age">;

type Intersection<T> = {
  [Key in keyof T]: T[Key];
};

type PartialByKeys<T, K extends keyof T = keyof T> = Omit<
  {
    [Key in K]?: T[Key];
  } & {
    [Key in keyof Omit<T, K>]: T[Key];
  },
  never
>;

type test2 = Omit<{ hello: "hi"; hi: "hello" }, "hello">;