title: Differences between express.Router and app.get?
body: <p>I'm starting with NodeJS and Express 4, and I'm a bit confused. I been reading the Express website, but can't see <em>when</em> to use a route handler or when to use <code>express.Router</code>.</p>
  
  <p>As I could see, if I want to show a page or something when the user hits <code>/show</code> for example I should use:</p>
  
  <pre><code>var express = require('express')    
  var app = express()    
  app.get("/show", someFunction)  
  </code></pre>
  
  <p>At the beginning, I thought this was old (for Express 3). Is that right or this is the way for Express 4 too?</p>
  
  <p>If this is the way to do it in Express 4, what is <code>express.Router</code> used for?</p>
  
  <p>I read almost the same example as above but using <code>express.Router</code>:</p>
  
  <pre><code>var express = require('express');
  var router = express.Router();
  router.get("/show", someFunction)
  </code></pre>
  
  <p>So, what's the difference between both examples? </p>
  
  <p>Which one should I use if I just want to do a simple testing website?</p>