auto animationsForComponents()

in ComponentKit/Core/CKComponentAnimations.mm [82:123]
35 lines of code
4 McCabe index (conditional complexity)

  auto animationsForComponents(const ComponentTreeDiff& animatedComponents, UIView *const hostView) -> CKComponentAnimations
  {
    if (animatedComponents.appearedComponents.empty() &&
        animatedComponents.updatedComponents.empty() &&
        animatedComponents.disappearedComponents.empty()) {
      return {};
    }

    const auto animationsOnInitialMountPairs = filter(map(animatedComponents.appearedComponents, [](const auto &c) {
      return std::make_pair(c, c.animationsOnInitialMount);
    }), [](const auto &pair) {
      return !pair.second.empty();
    });

    const auto animationsOnInitialMount =
    CKComponentAnimations::AnimationsByComponentMap(animationsOnInitialMountPairs.begin(),
                                                    animationsOnInitialMountPairs.end());

    const auto animationsFromPreviousComponentPairs = filter(map(animatedComponents.updatedComponents, [](const auto &pair) {
      return std::make_pair(pair.current, [pair.current animationsFromPreviousComponent:pair.prev]);
    }), [](const auto &pair) {
      return !pair.second.empty();
    });

    const auto animationsFromPrevComponent =
    CKComponentAnimations::AnimationsByComponentMap(animationsFromPreviousComponentPairs.begin(),
                                                    animationsFromPreviousComponentPairs.end());

    const auto animationsOnFinalUnmountPairs = filter(map(animatedComponents.disappearedComponents, [hostView](const auto &c) {
      return std::make_pair(c, map(c.animationsOnFinalUnmount, [hostView](const auto &a) {
        return CKComponentAnimation {a, hostView};
      }));
    }), [](const auto &pair) {
      return !pair.second.empty();
    });

    const auto animationsOnFinalUnmount =
    CKComponentAnimations::AnimationsByComponentMap(animationsOnFinalUnmountPairs.begin(),
                                                    animationsOnFinalUnmountPairs.end());

    return {animationsOnInitialMount, animationsFromPrevComponent, animationsOnFinalUnmount};
  }