how to write a get route for param in express code example

Example 1: express param in url

app.get('/p/:tagId', function(req, res) {
  res.send("tagId is set to " + req.params.tagId);
});

// GET /p/5
// tagId is set to 5

Example 2: express route parameters

app.get('/users/:userId/books/:bookId', function (req, res) {
  res.send(req.params)
})