title: javascript - app.set('port', 8080) versus app.listen(8080) in Express.js
body: <p>I've been trying to use Express.js to launch a website. At first, I was using
  <code>app.set('port', 8080)</code> but the browser was unable to connect to the page. Afterwards, I changed the code to <code>app.listen(8080)</code> and the webpage appeared normally.</p>
  
  <p>This led me to wonder, what is the difference between these two functions?</p>