Update route not working on merged express router params - node.js

Question

I'm learning the MERN stack and encountered an issue on the edit route of my child router.
I have the below model schemas in songs.js and students.js files:
const mongoose = require('mongoose');
const studentSchema = mongoose.Schema({
name: { type: String, required: true },
instrument: String,
songs: [{
type: mongoose.Schema.Types.ObjectId,
ref: 'Song'
}]
});
const Student = mongoose.model('Student', studentSchema);
module.exports = Student;
const mongoose = require('mongoose');
const songSchema = mongoose.Schema({
name: { type: String, required: true },
img: String
})
const Song = mongoose.model('Song', songSchema);
module.exports = Song
And I have songs.js and students.js files for my routers, with mergeParams set to true for my songs router const songs = express.Router({ mergeParams: true });. I'm attaching it to the students router like this:
students.use('/:id/songs', songs);
e.g., my url parameters become students/student1/songs/song1
All of my other routes are working, but on the update route of my songs router I'm getting an error "TypeError: Student.findById is not a function" when I redirect back to the song's index view. My edit and update routes
are below:
songs.get('/:songId/edit', async (req, res) => {
try {
const findSong = Song.findById(req.params.songId);
const findStudent = Student.findById = (req.params.id);
const [foundSong, foundStudent] = await Promise.all([findSong, findStudent]);
res.render('songs/edit', {
student: foundStudent,
song: foundSong
})
} catch (err) {
console.log(err);
}
});
songs.put('/:songId', async (req, res) => {
try {
const updateSong = await Song.findByIdAndUpdate(req.params.songId, req.body, { new: true });
res.redirect('/students/' + req.params.id + '/songs');
} catch (err) {
console.log(err);
}
});
I'm not sure what's causing the error here, my delete route is set up similarly and is working. Would appreciate any suggestions.

Answer 1

In your rote (req.params.id) is not defining.
songs.get('/:songId/edit', async (req, res) => {
try {
const findSong = Song.findById(req.params.songId);
**const findStudent = Student.findById = (req.params.id);**
const [foundSong, foundStudent] = await Promise.all([findSong, findStudent]);
res.render('songs/edit', {
student: foundStudent,
song: foundSong
})
} catch (err) {
console.log(err);
}
});