text: const INITIAL_STATE = { step: 1, number: 0 };
  
  export default function(state = INITIAL_STATE, action) {
    switch (action.type) {
      case 'INC':
        return { ...state, number: state.number + state.step };
      case 'DEC':
        return { ...state, number: state.number - state.step };
      case 'STEP_CHANGED':
        return { ...state, step: +action.payload };
      default:
        return state;
    }
  }
  