text: const userReducer = (state = {name: "Lloyd", age: 30}, action) =>{ 
      // A reducer always 
      //  handle actions
      //  return a state
          switch(action.type){
              case "SET_NAME": // by convention, action types is written in CAP
              state = { 
                  // spread your state and change selective values && make it immutable
                  ...state, 
                  name: action.payload
              }
              break;
              case "SET_AGE":
                  state ={
                      ...state,
                      age: action.payload
                  }
              break;
          }
          return state 
  }
  
  export default userReducer;