从文件夹ES6导入

Question

我正在学习JS，我有类似的东西。

//all inside folder reducers 

//reducer1.js 
export default reducer1 

//reducer2.js 
export default reducer2 

//index.js 
import reducer1 from './reducer1' 
import reducer2 from './reducer2' 
//then combine reducer 
export default index 

//outside folder reducers 
import reducer from './reducers' 

因为./reducers只是一个文件夹，并且有3个文件，3出口默认里面，我不明白这是怎么工作的？它如何知道文件夹中的哪个导出默认值将被导入？

谢谢。

Answer 1

使用Webpack，当您导入文件夹时，模块加载器将导入文件夹内的index.js。您正在index.js中导出索引，因此您在执行import reducer from './reducers'时会导入它。导入文件夹只是import reducer from reducers/index的简写。意思是两个进口声明是等价的。

总结起来，import reducer from './reducers'与import reducer from reducers/index相同。