title: How does express know this routing?
body: <p>I create a simple express server and serve the static files</p>
  
  <pre><code>const express = require('express');
  const app = express();
  
  app.use(express.static('public'));
  
  app.listen(3000, () =&gt; {
  console.log('Listening on port 3000')
  })
  </code></pre>
  
  <p>When I head to localhost:3000, the index.html in my public directory renders for the route ' / '. I didn't explicitly write the route in my index.js file. How does express know this?</p>
  
  <p>I've tried changing the file name from index.html to random.html and I get an error. CANNOT GET /</p>