Using output of one mongoose query for the input of another in express (async/await) - mongodb

Question

I am using express and mongoose to implement a server/db. I have a working route that gets all the games involving a player by playerID. I am now trying to implement one that can take username instead of playerID.
PLAYER_SCHEMA:
const mongoose = require('mongoose');
const PlayerSchema = mongoose.Schema( {
username: {
type:String,
required:true,
unique:true
},
date_registered: {
type: Date,
default:Date.now
}
});
module.exports = mongoose.model('Player', PlayerSchema);
GAME_SCHEMA:
const mongoose = require('mongoose');
const GameSchema = mongoose.Schema( {
player_1: {
type: mongoose.Schema.Types.ObjectId,
ref: 'Player',
required: true
},
player_2: {
type: mongoose.Schema.Types.ObjectId,
ref: 'Player',
required: true
},
status: {
type:String,
},
hero_1: {
type:String
},
hero_2: {
type:String
},
date_registered: {
type: Date,
default:Date.now
}
});
module.exports = mongoose.model('Game', GameSchema);
Here's what I have to query all games involving a player by playerId:
//GET GAMES INVOLVING PLAYER BY PLAYER_ID
router.get('/player/:playerId', async (req, res) => {
try {
const games = await Game.find({$or:[{ player_1: req.params.playerId }, { player_2: req.params.playerId}]});
console.log(games)
res.json(games);
// weird cuz doesn't throw error if not found, just returns empty list...
}
catch (err) {
res.json({ message: err });
}
});
The following outlines what I want to do, but it doesn't work, for I'm sure many reasons:
I am trying to get the userId from username first, then pass that into a query for the games.
//GET ALL GAMES ASSOCIATED WITH PLAYER BY USERNAME
router.get('/username/:username', async (req, res) => {
try {
const player = await Player.findOne({username:req.params.username});
console.log(player);
const games = Game.find({ $or:[{ player_1: player._id }, { player_2: player._id }] });
res.json(games);
}
catch (err) {
res.json({ message: err });
}
});
I've been reading about .populate(), promises, and waterfalls, but I'm new to this and would love some guidance!

Answer 1

Please try this :
//GET ALL GAMES ASSOCIATED WITH PLAYER BY USERNAME
router.get('/username/:username', async (req, res) => {
try {
const player = await Player.findOne({ username: req.params.username });
console.log(player);
/**
* .findOne() should return a document or null - if no match found..
*/
if (player) {
/**
* .find() will return empty [] only if it didn't find any matching docs but won't throw an error in successful DB operation
* (irrespective of whether docs matched or not, if op is successful then there will be no error).
*/
const games = await Game.find({ $or: [{ player_1: player._id }, { player_2: player._id }] }).lean();
(games.length) ? res.json(games) : res.json(`No games found for ${player._id}`);
} else {
res.json('No player found')
}
}
catch (err) {
res.json({ message: err });
}
});