text: let nextTodoId = 0
  
  export const addTodo = (text) => ({
    type: 'ADD_TODO',
    id: nextTodoId++,
    text
  })
  
  export const setVisibilityFilter = (filter) => ({
    type: 'SET_VISIBILITY_FILTER',
    filter
  })
  
  export const toggleTodo = (id) => ({
    type: 'TOGGLE_TODO',
    id
  })
  