cannot find method node.js module

I have a js file like this

loader.js
exports.getConfig = function() {
   return config;
}

I am loading this file in other file as

var loader = require(__dirname + '/../../loader');
var config = loader.getConfig();

But I am getting error as Object has no method getCOnfig() I checked the path the path in require is correct

Maybe you have made a circular require, it's not obvious,check it carefully:

If yes,learn more: https://coderwall.com/p/myzvmg

I say circular require,I mean suppose you have three module A,B,C. A require B,B require C,C require A. Yes,this is a circular require,this may cause strange error.

I don't know why somebody downvote my answer, I spent hours to figure out what happened when I get this error.I think this question probably is a circular require situation.