import { IIterator } from './iter' ; returns export function empty < T > ( ) { return new EmptyIterator < T > ( ) ; } /**
 * An iterator which is always empty.
 */ export class EmptyIterator < T > implements IIterator < T > { returns iter ( ) { return this ; } returns clone ( ) { return new EmptyIterator < T > ( ) ; } returns next ( ) { return undefined ; } }