MongoDB and Mongoose - id from two different collection queries not matching

Question

I'm building an app where people are able to make potlucks and invite other users to their potlucks. I have what seems to be a simple problem but I haven't been able to make it work:

I want to make an invite route that checks the potluck.attendees to see if they have been invited before (and send different errors depending on if they're 0-pending, 1-attending or re-invite them if they have been invited before and their status is 2 declined) and if not, puts the invitee into the potluck.attendees object array and the potluck's _id into the invitee's user.potlucks object array.

Here are super-trimmed versions of those two models:

Simplified Potluck Model

const PotluckSchema = new Schema({
  attendees: [
    {
      attendeeId: {
        type: mongoose.Schema.Types.ObjectId,
        ref: 'User'
      },
      status: Number,
      enums: [
        0, //'pending',
        1, //'attending',
        2 //'declined'
      ]
    }
  ]
});

Simplified User Model

const UserSchema = new Schema({
  potlucks: [
    {
      potluck: {
        type: mongoose.Schema.Types.ObjectId,
        ref: 'Potluck'
      }
    }
  ]
});

And what I have so far on this route is:

router.put('/attendees/invite/:potluckId/:inviteeId', async (req, res) => {
  try {
    const currPotluck = await db.Potluck.findOne({
      _id: req.params.potluckId,
      createdBy: req.user._id
    });
    // Makes sure potluck belongs to user before allowing to invite
    if (!currPotluck)
      return res.status(401).json({
        msg: 'You are not authorized to invite people to this potluck.'
      });
    const invitee = await db.User.findOne({ _id: req.params.inviteeId });

    console.log(currPotluck);
    console.log(invitee);

    for (let i = 0; i < currPotluck.attendees.length; i++) {
      //  Checks if invitee already exists in potluck.attendees
      //  and if their status is 0 or 1 (pending or attending)
      //  It will stop function
      if (
        currPotluck.attendees[i].attendeeId == invitee._id &&
        currPotluck.attendees[i].status == 0 ||
        currPotluck.attendees[i].attendeeId == invitee._id &&
        currPotluck.attendees[i].status == 1
      ) {
        return res.status(401).send({
          error: 'This member has already been invited to your potluck'
        });
      } else if (
        currPotluck.attendees[i].attendeeId == invitee._id &&
        currPotluck.attendees[i].status == 2
      ) {
        //  if their status is 2 (declined)
        //  it will edit their existing object in the attendees array to pending
        //  and re-insert potluck in invitee's user.potlucks model
        await db.Potluck.findOneAndUpdate(
          { _id: currPotluck._id },
          { $set: { 'attendees.$[el].status': 0 } },
          { arrayFilters: [{ 'el.attendeeId': invitee._id }] }
        );
        await db.User.findOneAndUpdate(
          { _id: invitee._id },
          { $push: { potlucks: { potluck: currPotluck._id } } }
        );
        res.send(`This user has been re-invited to your potluck!`);
      }
    }
    // If they don't exist already in potluck.attendees, create new object
    // in potlucks.attendees and user.potlucks for invitee
    await db.Potluck.findOneAndUpdate(
      { _id: currPotluck._id },
      { $push: { attendees: { attendeeId: invitee._id, status: 0 } } }
    );
    await db.User.findOneAndUpdate(
      { _id: invitee._id },
      { $push: { potlucks: { potluck: currPotluck._id } } }
    );
    res.send(`This user has been invited to your potluck!`);
  } catch (err) {
    console.error(err.message);
    res.status(500).send('Server Error');
  }
});

Now to the issue:

If I run this code in postman, it will run the two 'findOneAndUpdate's that come after the for-loop regardless if there is a match or not. When trying to debug, I console.logged both invitee._id and currPotluck.attendees[i].attendeeId (for a test where I knew the invitee already existed in the array) and they both come up as the same id.

But if I try to console.log (currPootluck.attendees[i].attendeeId == invitee._id) it comes up false every time. I did a 'type of' for both and they come up as objects, and they both appear to be the same type in console.logs - strings maybe?

I know the solution must be something super simple but I can't figure it out, any help would be much appreciated!

Answer 1

Both currPootluck.attendees[i].attendeeId and invitee._id are ObjectIds , in order to check if they are the same, you must first convert it to strings.

This should do the job: currPootluck.attendees[i].attendeeId.toString() == invitee._id.toString()