[Medium] Example of bad usage of redux

reducer.js

export default (action, state) => {
  switch(action.type) {
   case FIRST_EXAMPLE:
      return {
        ...state,
        quickbarIsOpen: true,
        dfes: {
          ...state.dfes,
          nfes: {
            ...state.dfes.nfes,
            data: state.dfes.nfes.data.map((nfe, index) => ({
              ...nfe,
              visible: index === action.index,
            }),
          },
        },
      }
    default:
      return state
  }
}