Mongoose: Match UserIDs with Embedded Document

Question

What i'm trying to achieve is matching people with each other. To achieve this behavior, i'm embedding Match document to user's matches array.

Heres my User Model

const mongoose = require('mongoose');
const Schema = mongoose.Schema;

const Match = new Schema({
    with: {type: Schema.Types.ObjectId, ref: 'User'},
    near: {type:String},
    createdAt: {type:Date, default: Date.now}
 });


const UserSchema = new Schema({
    name: { type: String, default: '' },
    surname: { type: String, default: '' },
    email: { type: String, default: '', },
    salt: { type: String, default: '' },
    hashed_password: { type: String, default: '' },
    interested: { type: [String] },
    about: { type: String },
    createdAt: {type:Date, default:Date.now},
    devices: {type: [String]},
    matches: [Match]
 });

But for a reliable application logic, The users must not be matched twice. My plan is inserting matched people inside their matches array together,

for example;

User A
_id: 123
matches: [{with: 456,near:California,createdAt:someDateTime}] 

User B
_id: 456
matches: [{with: 123,near:California,createdAt:someDateTime}] 

Before a match occurs, i need to control whether any of the users matched before or not and it must be atomic .

Thanks.

Answer 1

Maybe this works:

const Match = new Schema({
    matchedIds: [ {type:string} ]
    near: {type:String},
    createdAt: {type:Date, default: Date.now}
 });

So matchedIds just contains the two userIDs. You can find the match then with:

db.match.find( { matchedIds: { $all: ["UserID 1", "UserID 2"] } } )