title: var mqtt = require('mqtt'); resulting in error
body: <p>I have installed 'node.js' and then executed '<strong>npm install mqtt</strong>' from 'node.js' command line to install 'mqtt.js'. Now to test 'mqtt client' I am trying to execute :
          <strong>var mqtt = require('mqtt');</strong>
  which results in error saying:</p>
  
  <pre><code>  "Error: Cannot find module 'mqtt'
     at Function.Module._resolveFilename (module.js:338:15)
     at Function.Module._load (module.js:280:25)
     at Module.require (module.js:364:17)
     at require (module.js:380:17)
     at repl:1:12
     at REPLServer.self.eval (repl.js:110:21)
     at repl.js:249:20
     at REPLServer.self.eval (repl.js:122:7)
     at Interface.&lt;anonymous&gt; (repl.js:239:12)
     at Interface.EventEmitter.emit (events.js:95:17)"
  </code></pre>