Populate example

var mongoose = require('mongoose');
var mongoosePaginate = require('mongoose-paginate-v2');

mongoose.connect('mongodb+srv://...', { useNewUrlParser: true }); //INSERT YOUR CONNECTION URL HERE


var genreSchema = new mongoose.Schema({
    name: String
});

var gameSchema = new mongoose.Schema({
    name: String,
    genres: [{ genre: { type: mongoose.Types.ObjectId, ref: 'Genre' } }]
});

gameSchema.plugin(mongoosePaginate);

const Genre = mongoose.model('Genre', genreSchema);
const Game = mongoose.model('Game', gameSchema);

var gList = [
    'Action',
    'Horror',
    'Drama',
    'VR',
    'FPS'
];
//inserting genre:
Genre.insertMany(
    gList.map(e => {
        return {
            name: e
        }
    })
).then(doc => {
    console.log("inserted", doc)
    //looping through genre and adding a game which belong to each genre
    // converting doc array to desired format as specifeid in schema [{ genre: { type: mongoose.Types.ObjectId, ref: 'Genre' } }]
    var genArray = doc.map(gen => {
        return { genre: gen._id };
    }); //need _id field for population  to be done
    var AllGenreGame = new Game({ name: "All Genre Game", genres: genArray });
    AllGenreGame.save().then(async (sG) => {
        console.log("game saved", sG);
        // game saved now  we can query it:
        var result = await Game.paginate({}, {
            page: 1,
            limit: 10,
            populate: 'genres.genre'
        });
        console.log("RESULT IS", result);
        console.log("populated array", result.docs[result.docs.length - 1].genres);
    })
})