title: Best practices for using ExpressJS middleware across a number of different files in NodeJS app
body: <p>If I wanted to utilise useful middleware like <code>express.cookieParser();</code> and suchlike, am I expected to be economical with my instances of express when splitting my NodeJS application up into different files.</p>
  
  <p>For example, if I use <code>var express = require('express')</code> in one file, and again in many others, am I wasting resources fetching these and re-instantiating them? Or does <code>require</code> cache modules, or (even better) create a global instance of them?</p>
  
  <p>I know the performance impact of requiring express on multiple files would probably be negligible - this is more of a question to help me understand how modules load.</p>