vr module reducer

vr_module_reducer.ts

const vrModuleReducer: ActionReducer<IVrModule[]> = (state: IVrModule[] =
                                                    initialState, action: Action) => {
  switch (action.type) {
    case VR_MODULE_REMOVED:
      return _.filter(state, (mod) => mod.id === action.payload.id);
    case VR_MODULE_ADDED:
      return _.concat(state, action.payload);
    default:
      return state;
  }
};