debounce.js

  var DebounceObservable = (function (__super__) {
    inherits(DebounceObservable, __super__);
    function DebounceObservable(source, dt, s) {
      isScheduler(s) || (s = defaultScheduler);
      this.source = source;
      this._dt = dt;
      this._s = s;
      __super__.call(this);
    }

    DebounceObservable.prototype.subscribeCore = function (o) {
      var cancelable = new SerialDisposable();
      return new BinaryDisposable(
        this.source.subscribe(new DebounceObserver(o, this._dt, this._s, cancelable)),
        cancelable);
    };

    return DebounceObservable;
  }(ObservableBase));

  var DebounceObserver = (function (__super__) {
    inherits(DebounceObserver, __super__);
    function DebounceObserver(observer, dueTime, scheduler, cancelable) {
      this._o = observer;
      this._d = dueTime;
      this._scheduler = scheduler;
      this._c = cancelable;
      this._v = null;
      this._hv = false;
      this._id = 0;
      __super__.call(this);
    }

    function scheduleFuture(s, state) {
      state.self._hv && state.self._id === state.currentId && state.self._o.onNext(state.x);
      state.self._hv = false;
    }

    DebounceObserver.prototype.next = function (x) {
      this._hv = true;
      this._v = x;
      var currentId = ++this._id, d = new SingleAssignmentDisposable();
      this._c.setDisposable(d);
      d.setDisposable(this._scheduler.scheduleFuture(this, this._d, function (_, self) {
        self._hv && self._id === currentId && self._o.onNext(x);
        self._hv = false;
      }));
    };

    DebounceObserver.prototype.error = function (e) {
      this._c.dispose();
      this._o.onError(e);
      this._hv = false;
      this._id++;
    };

    DebounceObserver.prototype.completed = function () {
      this._c.dispose();
      this._hv && this._o.onNext(this._v);
      this._o.onCompleted();
      this._hv = false;
      this._id++;
    };

    return DebounceObserver;
  }(AbstractObserver));

  function debounceWithSelector(source, durationSelector) {
    return new AnonymousObservable(function (o) {
      var value, hasValue = false, cancelable = new SerialDisposable(), id = 0;
      var subscription = source.subscribe(
        function (x) {
          var throttle = tryCatch(durationSelector)(x);
          if (throttle === errorObj) { return o.onError(throttle.e); }

          isPromise(throttle) && (throttle = observableFromPromise(throttle));

          hasValue = true;
          value = x;
          id++;
          var currentid = id, d = new SingleAssignmentDisposable();
          cancelable.setDisposable(d);
          d.setDisposable(throttle.subscribe(
            function () {
              hasValue && id === currentid && o.onNext(value);
              hasValue = false;
              d.dispose();
            },
            function (e) { o.onError(e); },
            function () {
              hasValue && id === currentid && o.onNext(value);
              hasValue = false;
              d.dispose();
            }
          ));
        },
        function (e) {
          cancelable.dispose();
          o.onError(e);
          hasValue = false;
          id++;
        },
        function () {
          cancelable.dispose();
          hasValue && o.onNext(value);
          o.onCompleted();
          hasValue = false;
          id++;
        }
      );
      return new BinaryDisposable(subscription, cancelable);
    }, source);
  }

  observableProto.debounce = function () {
    if (isFunction (arguments[0])) {
      return debounceWithSelector(this, arguments[0]);
    } else if (typeof arguments[0] === 'number') {
      return new DebounceObservable(this, arguments[0], arguments[1]);
    } else {
      throw new Error('Invalid arguments');
    }
  };