How to push an object into the model array only if it is not there?

Question

MongoDB

There is such a scheme:

const chat = new schema({
  name: {
    type: String,
    required: true,
    unique: true,
  },
  users: [{
    name: {
      type: String,
      required: true,
      unique: true,
    }
  }],
  messages: [{
    user: {
      type: String,
      required: true,
    },
    message: {
      type: String,
      required: true,
    },
    date: {
      type: String,
      required: true,
    }
  }]
}, {
  versionKey: false,
  collation: 'chat'
});

There is a request, the user is looking for chats, if he finds them, then he can join them (to 1 at a time (per request)).

It looks something like this:

router.post('/join', async (request, response) => {
  models.chat.findOneAndUpdate({
    name: request.body.data.chat.name
  }, {
    $push: {
      users: {
        name: request.body.data.user.name,
      }
    }
  }, {
    new: true,
    upsert: true,
  }, (error, chat) => {
    if (!error){
      response.json({
        status: true,
        body: {
          chat
        },
      });

      //console.log('Chat update! chat: ', chat);
    } else {
      //console.log('error: ', error);
    }
  });
});

I can’t understand if I can somehow indicate that if the users array already has an object with the name that comes in the request, then nothing needs to be done?

Answer 1

Change $push to $addToSet and voila ))