Redux, https://github.com/reactjs/redux/blob/master/examples/todomvc/src

actions

export const addTodo = text => ({ type: types.ADD_TODO, text })
export const deleteTodo = id => ({ type: types.DELETE_TODO, id })
export const editTodo = (id, text) => ({ type: types.EDIT_TODO, id, text })

constants

export const ADD_TODO = 'ADD_TODO'
export const DELETE_TODO = 'DELETE_TODO'
export const EDIT_TODO = 'EDIT_TODO'

Reducer

export default function todos(state = initialState, action) {
  switch (action.type) {
    case ADD_TODO:
      return [
        {
          id: state.reduce((maxId, todo) => Math.max(todo.id, maxId), -1) + 1,
          completed: false,
          text: action.text
        },
        ...state
      ]
    case DELETE_TODO:
      return state.filter(todo =>
        todo.id !== action.id
      )
  })