在节点module.exports中的对象方法中使用'this'

Question

Here is my module:

module.exports = {

    name: '',
    email: '',
    id: '',
    provider: '',
    logged_in: false,

    isLoggedIn: function(req, res, next){
        console.log(this);

    }   
};

I import it like so:

var user = require('user');

When I use the isLoggedIn function as middle with Express, the console logs the global Node object. How do I get it to log the object the function is within?

EDIT

So I have my user object as defined above. Depending on various factors this object is populated elsewhere in the program. I with to create a middleware function for express to quickly test of the user is logged in. The obvious place to put this function seemed to be in the user object, but I need access to the logged_in property to evaluate it properly. Hence use of this.logged_in.

Answer 1

You should put that with IIFE:

module.exports = (function() {
    return {
      name: '',
      email: '',
      id: '',
      provider: '',
      logged_in: false,

      isLoggedIn: function(req, res, next){
        console.log(this);
      }   
   }
})();

You could read about here: http://designpepper.com/blog/drips/an-introduction-to-iifes-immediately-invoked-function-expressions

Answer 2

When you pass that as a middle function, I believe you are doing something like ths

func(.., user.isLoggedIn, ..)

When you are doing like this, you are actually detaching isLoggedIn from the user object. So, by default, if not in strict mode, this will refer to global object. To fix this, you should bind the function, like this

func(.., user.isLoggedIn.bind(user), ..)