talk/client/talk-plugin-commentbox/reducer.js

import { ADD_TAG, REMOVE_TAG, CLEAR_TAGS } from './constants';

const initialState = {
  tags: [],
};

export default function commentBox(state = initialState, action) {
  switch (action.type) {
    case ADD_TAG:
      return {
        ...state,
        tags: [...state.tags, action.tag],
      };
    case REMOVE_TAG:
      return {
        ...state,
        tags: [
          ...state.tags.slice(0, action.idx),
          ...state.tags.slice(action.idx + 1),
        ],
      };
    case CLEAR_TAGS:
      return initialState;
    default:
      return state;
  }
}