PartiallyRequired.ts

type PartiallyRequired<T, K extends keyof T> = Pick<T, K> & Partial<T>;

type Test = {
  foo: string;
  bar: string;
  baz: string;
};

type Test1 = PartiallyRequired<Test, "foo">;

// Will error if foo is not included. bar, baz optional.
const test1: Test1 = {
  foo: '',
  bar: '',
  baz: ''
}

type Test2 = PartiallyRequired<Test, "bar" | "baz">;

// Both bar and baz must be included. foo optional.
const test2: Test2 = {
  foo: '',
  bar: '',
  baz: ''
}