Back navigation with custom animations

[bataevvlad]

When we add fadeIn animation to our stackNavigator for several screens, sometime we have issue that our animation applied in both ways of navigating. We solved it by adding isActive.

// Custom transitions go there
  if (prevScene
    && prevScene.route.routeName === 'ScreenA'
    && nextScene.route.routeName === 'ScreenB'
    && nextScene.isActive) {
    return fadeIn();
  }
  return null;
}

I hope this solution will help those who want to use navigation only in one direction.