Coursemology/coursemology2

import { arrayToObjectWithKey } from 'utilities/array';

import actions from '../constants';

export default function (state = {}, action) {
  switch (action.type) {
    case actions.FETCH_SUBMISSION_SUCCESS:
      return {
        ...state,
        ...arrayToObjectWithKey(action.payload.topics, 'id'),
      };
    case actions.CREATE_COMMENT_SUCCESS: {
      const { topicId, id: postId } = action.payload;
      return {
        ...state,
        [topicId]: {
          ...state[topicId],
          postIds: [...state[topicId].postIds, postId],
        },
      };
    }
    case actions.DELETE_COMMENT_SUCCESS: {
      const { topicId, postId } = action.payload;
      return {
        ...state,
        [topicId]: {
          ...state[topicId],
          postIds: state[topicId].postIds.filter((id) => id !== postId),
        },
      };
    }
    default:
      return state;
  }
}