03188-medium-tuple-to-nested-object.ts

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

type cases = [
  Expect<Equal<TupleToNestedObject<['a'], string>, { a: string }>>,
  Expect<Equal<TupleToNestedObject<['a', 'b'], number>, { a: { b: number } }>>,
  Expect<
    Equal<
      TupleToNestedObject<['a', 'b', 'c'], boolean>,
      { a: { b: { c: boolean } } }
    >
  >,
  Expect<Equal<TupleToNestedObject<[], boolean>, boolean>>
]

// ============= Your Code Here =============
type TupleToNestedObject<T extends PropertyKey[], U> = T extends [
  infer First extends PropertyKey,
  ...infer Rest extends PropertyKey[]
]
  ? {
      [P in First]: TupleToNestedObject<Rest, U>
    }
  : U