00645-medium-diff.ts

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

type Foo = {
  name: string
  age: string
}
type Bar = {
  name: string
  age: string
  gender: number
}
type Coo = {
  name: string
  gender: number
}

type cases = [
  Expect<Equal<Diff<Foo, Bar>, { gender: number }>>,
  Expect<Equal<Diff<Bar, Foo>, { gender: number }>>,
  Expect<Equal<Diff<Foo, Coo>, { age: string; gender: number }>>,
  Expect<Equal<Diff<Coo, Foo>, { age: string; gender: number }>>,
]


// ============= Your Code Here =============

type Diff<O, O1> = {
 [P in Exclude<keyof O | keyof O1, keyof O & keyof O1>] : P extends keyof O? O[P] : P extends keyof O1? O1[P] : never
};

type A = keyof Foo
type B = keyof Bar
type C = A & B // "name" | "age"
type D = A | B // "name" | "age" | "gender"