The Extract function will extract types from Left that extend Right.
Example usage is shown below.
const L = Type.Union([
Type.Literal('hello'),
Type.Literal('world'),
Type.Literal(1),
Type.Literal(2)
])
const R = Type.String()
const S = Type.Extract(L, R) // const S: TUnion<[
// TLiteral<'hello'>,
// TLiteral<'world'>
// ]>