MongoDB - addToSet not adding element to array - node.js

Question

"mongoose": "^5.12.2"
I have a schema named User. This schema has a field named "rol" of type string[] for a multiple rol application (User, Admin, Freetour, BarOwner, etc).
The function that adds a rol to a user is defined like this:
public addRolToUser = (idUser:string, newRol:string):Promise<IUser> => {
try{
return new Promise<IUser>((resolve, reject) => {
User.findByIdAndUpdate(idUser, { addToSet: {rol:newRol} }, {new:true}).then(user => {
return resolve(user);
}).catch(err => {
return reject(err);
});
});
}catch (e) {
throw e;
}
};
However this doesn´t update the "rol" field of the user. The following function should add the rol "FreeTour" to the user with the id returned by "petition.user".
public acceptPetition = async(req:Request, res:Response) => {
try{
return this.solFreeTourService.acceptPetition(req.body.idPetition).then(petition => {
let acceptPromise = new Promise((resolve, reject) => {
// Here I´m invoking the addRolToUser function
return this.userService.addRolToUser(petition.user, "FREETOUR").then((resUser)=>{
// resUser here has the same value for the "rol" field, didn´t get updated.
return resolve(petition);
}).catch(err=>{
return reject(err);
})
})
return acceptPromise.then(petition=>{
return res.status(200).json({petition});
}).catch(e=>{
res.status(400).json({ status: 400, message: "There has been an error." });
});
})
}catch (e) {
res.status(400).json({ status: 400, message: "There has been an error." });
}
}
I don't want repeated values in the "rol" array, hence pushing is not an option.
What am I doing wrong?

Answer 1

first of all, Welcome to StackOverflow! 👋
I have to assume that you might have something not working well together as you say you're using Mongoose and for such I've made a very simple project that you can look into in GitHub
where I create a very simple schema
const UserSchema = mongoose.Schema({
role: [{
type: String
}],
guid: {
type: String,
required: true
},
});
and then make use of the Mongoose API to create, update and find the user
const guid = uuidv4();
// create user
await UserModel.create({ guid });
log('user created');
["admin", "user", "admin"].forEach(async (role) => {
// add role to user
await UserModel.updateOne({ guid }, { $addToSet: { role } });
log(`user role updated with ${role}`);
});
// read user
const newUser = await UserModel.where({ guid }).findOne();
log(JSON.stringify(newUser, null, 2));
and the output is the expected one
user created
user role updated with admin
user role updated with user
user role updated with admin
{
"role": [
"admin",
"user"
],
"_id": "60a2397b1c488d4968d6ed46",
"guid": "26ccacbf-ddbc-4cbf-ac69-2da3235e156b",
"__v": 0
}
fell free to look into the source code, clone, run, and test, and notice that I'm using in fact the Mongo command as $addToSet