freeCodeCamp/guide/english/certifications/front-end-libraries/redux/use-the-spread-operator-on-arrays/index.md

title

title
Use the Spread Operator on Arrays

Use the Spread Operator on Arrays

Solution

const immutableReducer = (state = ['Do not mutate state!'], action) => {
  switch(action.type) {
    case 'ADD_TO_DO':
      // don't mutate state here or the tests will fail
      let arr = [...state];
      arr.push(action.todo);
      return arr;
    default:
      return state;
  }
};

const addToDo = (todo) => {
  return {
    type: 'ADD_TO_DO',
    todo
  }
}

const store = Redux.createStore(immutableReducer);