Mongoose problem with object id "Cast to ObjectId failed for value" - node.js

Question

It's along explanation so to make it easier I'll call users x and y.
I got this code, which the intention is to the X (making the requests) add his ID into Y's pending requests as well as his own sent requests.
const postSendBBRequest = async (req, res) => {
const userRecipient = await User.findById(req.params.id)
const userSender = await User.findById(req.userId);
const senderId = userSender.id;
try {
if (senderId == userRecipient.id) {
res.status(406).json("You cannot have yourself as a brother")
} else {
userSender.sentBBRequests.push({senderId});
await userSender.save();
userRecipient.receivedBBRequests.push({senderId});
await userRecipient.save();
res.status(201).json("Brotheband request sent sucessfully")
}
} catch (ERR) {
res.status(500).json({ Message: ERR.message });
}
}
My test route on Postman is /add/61b29bb33e775393ae369b79
The problem is: I'm getting an error: "Cast to ObjectId failed for value \"{ senderId: '61b29aef3e775393ae369b74' }\" (type Object) at path \"sentBBRequests\
I thought maybe the problem was how I organized my Schema too:
receivedBBRequests: [
{
type: mongoose.Schema.Types.ObjectId,
},
],
sentBBRequests: [
{
type: mongoose.Schema.Types.ObjectId,
},
],
brothers: {
type: [
{
type: mongoose.Schema.Types.ObjectId,
},
]}
There are too many points of failure I can't even come up with something to solve.
Thanks a lot.

Answer 1

You can use the following :
const senderId = userSender._id.toString();
const userRecipientId = userRecipient._id.toString();
this will allow you to convert the objectId to string