PartialBy, make properties in typescript type optional

PartialBy.ts

/**
 * Construct a type with the properties of T and make the properties K optional.
 */
type PartialBy<T, K extends keyof T> = Omit<T, K> & Partial<Pick<T, K>>;

// Example:
type Person = {
  name: string;
  age: number;
  gender: "male" | "female";
};

type PersonWithOptionalAgeAndGender = PartialBy<Person, "age" | "gender">;