type Prettify<T> = {
  [K in keyof T]: T[K];
} & {};

export type Merge<A, B> = Prettify<
  Omit<A, keyof B> & B
>;

// Usage
type Base = { name: string; age: number };
type Override = { age: string; email: string };

type Merged = Merge<Base, Override>;
// { name: string; age: string; email: string }