I don’t understand the principle, please ask God for enlightenment!
Because bar is redefined when called for the second time, and the function does not allow repeated definitions
Repeated call
![[Web front-end] Node.js quick start](https://img.php.cn/upload/course/000/000/067/662b5d34ba7c0227.png)
Because bar is redefined when called for the second time, and the function does not allow repeated definitions
Repeated call