optional-props-pick.ts

type Optional<T, K extends keyof T> = Omit<T, K> & Partial<T>;

type Test = {
  foo: string,
  bar: string,
  baz: string,
  daz?: string,
}

type Test1 = Optional<Test, 'foo'>

const test1: Test1 = {
  bar: '',
  baz: '',
}

type Test2 = Optional<Test, 'bar' | 'baz'>

const test2: Test2 = {
  foo: '',
}