import { Operation , RequestHandler , NextLink , FetchResult } from '../types' ; import Observable from 'zen-observable-ts' ; import { ApolloLink } from '../link' ; export default class MockLink extends ApolloLink { constructor ( handleRequest = ( ) => null ) { super ( ) ; this . request = handleRequest ; } public request ( operation , forward ? ) { throw Error ( 'should be overridden' ) ; } }