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 MergeProperties<T> = {
  [P in keyof T]: T[P]
}
type Diff<O, O1> = MergeProperties<{
  [P in keyof O as P extends keyof O1 ? never : P]: O[P]
} & {
  [P in keyof O1 as P extends keyof O ? never : P]: O1[P]
}>

type Test = Diff<Foo, Bar>