CODEWITHSUNDEEP
node.jsmongodbmongoose
Greg Clark
Greg Clark

Reputation: 11

How can I match all values nested in a collection to values in another collection (mongodb)?

I am creating a messaging app and I need to be able to display the users with which a given user has conversation history. I have users and conversations. The models are below. (There is a messages collection where each document refers to a conversation)

//This is the conversation model.
const mongoose = require('mongoose');
const ConversationSchema = new mongoose.Schema({
  participants: {
    type: Array,
    required: true
  }
});
const Conversation = mongoose.model('Conversation', ConversationSchema);

//This is the users model (there's more to it, but this is the relevant stuff)
module.exports = Conversation;
const UserSchema = new mongoose.Schema({
  firstName: {
    type: String,
    required: true
  },
  lastName: {
    type: String,
    required: true
  }
});
const User = mongoose.model('User', UserSchema);
module.exports = User;

Each has an _id that is generated. I am sending an http request with a user ID. In my controller, using mongoose, I am able to do the following:

Conversation.find({participants:req.params.user_id})

This returns an array of conversation objects, each of which contains a participants array(an array of user IDs). What I then need to do is match all the participants to the "users" collection so I can get the user ID, first name and last name of each user.

In summary, I need to send an HTTP request with a user ID as a parameter and receive an array of users which have conversation history with the provided user.

What is the next step? How can I match the user IDs I get from the relevant conversations to the user IDs in the users collection?

Upvotes: 0

Views: 32

Answers (1)

Wicak
Wicak

Reputation: 409

Try with this

app.post('/:user_id', async(req, res) => {
 const partisipant = await Conversation.find({id:req.params.user_id});
 const userData = await User.find({id:req.params.user_id});
 if(!userData || userData != partisipant){
  throw ('no data match')
 }
 //...if found the data, do anything you want
})

Using async await to get collection data from database, and compare them.

Hope this clue can help you

Upvotes: 0

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