How to change the state in the reducer?

Question

React Native

Hey! This is my reducer
const initialState = {
items: {
First: 0,
Second: 0,
Third: 0
},
sum: 0
}

export default function fwReducer(state = initialState, action) {
switch (action.type) {
case ('INC '): {
const name = action.payload;
let newState = { ...state };
newState.items[name] += 1;
return { items: {...newState.items }, sum: state.total+1};
}
default: return state
}
}

I understand that now I am changing the state incorrectly, + in fact I am changing the array in the original store, mutating it, which is impossible. How should it be? Help me please)

Answer 1

You started to rebuild the state

let newState = { 
  ...state,
   items: {
     ...state.items,
     [name]: state.items[name] + 1,
     sum: state.sum+1
   }
};

Didn't have enough patience?