/// module Rx { export interface Observable { /** * Returns the last element of an observable sequence that satisfies the condition in the predicate if specified, else the last element. * @returns {Observable} Sequence containing the last element in the observable sequence that satisfies the condition in the predicate. */ last(predicate?: _Predicate, thisArg?: any): Observable; } } (function () { var o : Rx.Observable; o = o.last((x) => true); o = o.last((x) => true, {}); });