Type Alias UnionToIntersection<U>

UnionToIntersection: (U extends any ? (k: U) => void : never) extends (
    k: infer I,
) => void
    ? I
    : never

Convert a union to an intersection

type U = { a: number } | { b: string };
type I = UnionToIntersection<U>;
// { a: number } & { b: string }