Express.js - Dynamic Route Parameter Not Being Parsed Correctly in Nested Routes
I'm following best practices but I've spent hours debugging this and I'm currently developing an Express.js application (version 4.17.1) with nested routes, but I'm encountering an issue where the dynamic route parameter is not being parsed correctly when I call a nested route... The structure of my routes is as follows: ```javascript const express = require('express'); const router = express.Router(); router.get('/users/:userId', (req, res) => { res.send(`User ID: ${req.params.userId}`); }); router.get('/users/:userId/posts/:postId', (req, res) => { res.send(`User ID: ${req.params.userId}, Post ID: ${req.params.postId}`); }); module.exports = router; ``` In my main `app.js`, I mount the router like this: ```javascript const express = require('express'); const app = express(); const userRoutes = require('./routes/userRoutes'); app.use('/api', userRoutes); app.listen(3000, () => { console.log('Server is running on port 3000'); }); ``` When I try to access the route `http://localhost:3000/api/users/123/posts/456`, I'm expecting to see the response `User ID: 123, Post ID: 456`, but instead, I receive: ``` User ID: 123, Post ID: undefined ``` I've checked that the URL is correctly formatted and that the route handler for the nested route is being executed. I also tried adding some console logs to inspect `req.params`, and it shows `userId: '123'` but `postId` is missing. I am certain that I'm hitting the right endpoint, and I've ensured that I haven't inadvertently created overlapping routes. Could there be an issue with how I'm defining or accessing the dynamic parameters? What am I missing here? I recently upgraded to Javascript 3.9. I'm open to any suggestions. My development environment is macOS. Any advice would be much appreciated.