text: 
  const initialState = {
      age:20
  };
  
  const reducer = (state = initialState, action) => {
   const newState = {...state};
  
   if(action.type == 'Age_Up'){
       newState.age++;
   }
  
   if(action.type == 'Age_Down'){
       newState.age--;
   }
  
   return newState;
  }
  
  export default reducer;