title: Does Express.js on Node.js have a memory leak?
body: <p>I have been using express on node.js running on a heroku server for a simple project. When I started using new relic to monitor the memory I noticed a slow memory leak pattern. I removed all the code I developed and all other node modules and left only express itself and new relic modules. I still observe the memory leak. 
  I was wondering if this is express.js memory leak. 
  <img src="https://i.stack.imgur.com/lKXSV.png" alt="Here is the graphic from new relic"> </p>
  
  <p>Here is all the code left:</p>
  
  <pre><code>require('newrelic');
  var express = require('express'); 
  var app = express();
  var env = process.env.NODE_ENV || 'development';
  if ('development' == env) {
      app.set('port', process.env.PORT || 3000);
  }
  app.get('/', function ( req, res ) {
      res.send('The server is up and running!');
  });
  app.listen(app.get('port'), function() {
      console.log('Express server listening on port %d in %s mode', app.get('port'), app.get('env'));
  });
  </code></pre>
  
  <p>And package.json </p>
  
  <pre><code>{
    "name": "memleakdebug",
    "version": "1.0.0",
    "description": "",
    "main": "index.js",
    "scripts": {
      "test": "echo \"Error: no test specified\" &amp;&amp; exit 1"
    },
    "author": "",
    "license": "ISC",
    "dependencies": {
      "express": "^4.11.2",
      "newrelic": "^1.16.2"
    }
  }
  </code></pre>
  
  <p><strong>UPDATE1:</strong> Now growing memory even passed heroku's limit 512MB for free tiers.
  Garbage collection doesn't seem to work. </p>
  
  <p><img src="https://i.stack.imgur.com/FKmWG.png" alt="Memory keeps growing"> </p>