index.jsx

  componentDidUpdate: function(prevProps, prevState) {
    var _this = this, shouldTransition, shouldStartAnimation;

    shouldStartAnimation = this.state.transitionStarted && !this.state.isTransitioning;

    if (shouldStartAnimation) {
      this.setState({ isTransitioning: true });
    }

    shouldTransition = !this.state.transitionStarted &&
                       !this._equalScreens(this.state.activeScreen, this.state.screensStackTop);

    if (shouldTransition) {
      this.setState({
        transitionStarted: true,
        transitionDirection: this.state.activeScreen.get('stackIndex') > this.state.screensStackTop.get('stackIndex') ? "back" : "fwd"
      });

      setTimeout(function() {
        _this._resetTransition();
      }, 1000);
    }
  },