gengitkan/client/src/store/reducers/boards.ts

import { SAVE_BOARD_SUCCESS, FETCH_BOARDS_SUCCESS } from "../actions/boards";

export const defaultState = {
  byID: {},
};

export function boardsReducer(state = defaultState, action: any) {
  switch(action.type) {
    case SAVE_BOARD_SUCCESS:
      return handleSaveBoardSuccess(state, action);
    case FETCH_BOARDS_SUCCESS:
      return handleFetchBoardsSuccess(state, action);
    default:
      return state;
  }
}

function handleSaveBoardSuccess(state: any, action: any) {
  const { board } = action;
  return {
    ...state,
    byID: {
      ...state.byID,
      [board.id]: {
        ...board,
      }
    }
  };
}

function handleFetchBoardsSuccess(state: any, action: any) {
  const boardsByID = action.boards.reduce((byID: any, board: any) => {
    byID[board.id] = board;
    return byID;
  }, {});
  return {
    ...state,
    byID: {
      ...boardsByID,
    }
  };
}