1case ADD_ITEM :
2 return {
3 ...state,
4 arr: [...state.arr, action.newItem]
5 }
1case ADD_ITEM :
2 return {
3 ...state,
4 arr: [...state.arr, action.newItem]
5 }
6OR
7
8case ADD_ITEM :
9 return {
10 ...state,
11 arr: state.arr.concat(action.newItem)
12 }
13