In React app, you might create lots of components.
We can use index.js to do both ‘import‘ & ‘export‘.
export {TodoForm} from ‘./TodoForm‘
export {TodoList} from ‘./TodoList‘
When using it, we just need to import the folder:
import {TodoForm, TodoList} from ‘./components/todo‘
原文：http://www.cnblogs.com/Answer1215/p/6359046.html