Where is require('cookieParser') present in express 3?

I am writing a node js application and trying to use cookieParser in the below way:-

var express = require('express');
var app = express();
app.use(express.cookieParser());

I can find cookieParser.js which is present in the connect. I can also see that we are exporting this cookieParser function in cookieParser.js. However I am unable to find the place where we are using require('ccokieParser') in express or connect, even though I can use cookieParser by calling express.cookieParser()