:filename: ./app.js
.{filename}
[source,javascript]
----
const express = require('express'); <1>
const app = express();
app.get('/', (req, res) => { <2>
res.send('Hello World!');
});
app.listen(3000); <3>
----
<1> Import the Express framework
<2> Define a route handler
<3> Start the server on port 3000