Code Quiz

Redux Reducer State Mutation Bug

Spot the state-mutation bug that breaks Redux change detection in a reducer.

Codejavascript

const initialState = { items: [], count: 0 };

function cartReducer(state = initialState, action) {
  switch (action.type) {
    case 'ADD_ITEM':
      state.items.push(action.payload);
      state.count += 1;
      return state;
    case 'RESET':
      return initialState;
    default:
      return state;
  }
}

export default cartReducer;

What is the bug in this reducer?

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