node.js中的（）post require（）的用途是什么？

Question

I understand require() is used to import a particular node module into another and use it. But what is the use of using additional () post that. Say i have following require statement in my server.js file : var init = require('./config/init'); . It just means that we are importing modules declared in ./config/init.js file. But what does var init = require('./config/init')(); mean ? What is the use of () at the end of require statement ?

Answer 1

Simply that if this line imports a function :

var init = require('./config/init')

...then the additional () executes that function immediately.

Think of it as shortcut for these 2 lines

var initLib = require('./config/init')
var init = initLib();

Answer 2

require('library') returns the exports of the specified library. In this case, it looks like the library returns a function, and you're simply calling that and storing the value returned from the function.

In this case the module you're importing has code like this:

module.exports = function() {
    ...
    return theInitValue;
}