express get url parameters

const express = require('express');
const app = express();

app.get('/user/:id', (req, res) => {
  res.send('User ID: ' + req.params.id);
});

app.listen(3000, () => {
  console.log('Server is running on port 3000');
});

This Node.js code uses the Express framework to create a server. It defines a route using app.get() for the '/user/:id' URL pattern. When a request is made to this route, the callback function (req, res) => { ... } is executed. Inside this function, req.params.id retrieves the value of the 'id' parameter from the URL. The server responds by sending a message containing the retrieved 'id' parameter to the client. The app.listen() method starts the server on port 3000, and a message is logged to the console confirming the server is running.