Meteorboard - UI reducer

reducer.js

import * as actions from './actions';
import {Record} from 'immutable';

const InitialState = Record({
  isSideMenuOpen: false
});
const initialState = new InitialState;

export default function uiReducer(state = initialState, action) {
  if (!(state instanceof InitialState)) return initialState;

  switch (action.type) {

    case actions.ON_SIDE_MENU_CHANGE: {
      const {isOpen} = action.payload;
      return state.set('isSideMenuOpen', !isOpen);
    }

    case actions.TOGGLE_SIDE_MENU:
      return state.update('isSideMenuOpen', isSideMenuOpen => !isSideMenuOpen);

  }

  return state;
}