toset.js

  function toSet(source, type) {
    return new AnonymousObservable(function (observer) {
      var s = new type();
      return source.subscribe(
        s.add.bind(s),
        observer.onError.bind(observer),
        function () {
          observer.onNext(s);
          observer.onCompleted();
        })
    });
  }
  
  if (!!window.Set) {
    Rx.Observable.prototype.toSet = function () {
      return toSet(this, window.Set);
    };
  }
  
  if (!!window.WeakSet) {
    Rx.Observable.prototype.toWeakSet = function () {
      return toSet(this, window.WeakSet);
    };  
  }