Call a related collection via populate - node.js

Question

I try to call a related list of logs for a certain user via Mongoose populate. Who can help me with finishing the response?
These are the schemes:
const logSchema = new Schema({
logTitle: String,
createdOn:
{ type: Date, 'default': Date.now },
postedBy: {
type: mongoose.Schema.Types.ObjectId, ref: 'User'}
});
const userSchema = new Schema({
firstName: {
type: String,
required: true
},
lastName: {
type: String,
required: true
}
logs: { type: mongoose.Schema.Types.ObjectId, ref: 'logs' }
});
mongoose.model('User', userSchema);
mongoose.model('logs', logSchema);
Inspired by the Mongoose documentary (see above) and other questions in relation to this subject I think I got pretty far in making a nice get. request for this user. I miss the expierence to 'translate it' to Express.
const userReadLogs = function (req, res) {
if (req.params && req.params.userid) {
User1
.findById(req.params.userid)
.populate('logs')
.exec((err, user) => {
if (!user) { }); // shortened
return;
} else if (err) {
return; // shortened
}
response = { //question
log: {
user: user.logs
}
};
res
.status(200)
.json(response);
});
} else { }); //
}
};
The response in Postman etc would be something like this:
{
"log": {5a57b2e6f633ce1148350e29: logTitle1,
6a57b2e6f633ce1148350e32: newsPaper44,
51757b2e6f633ce1148350e29: logTitle3
}

Answer 1

First off, logs will not be a list of logs; it will be an object. If you want multiple logs for each user, you will need to store is as an array: logs: [{ type: mongoose.Schema.Types.ObjectId, ref: 'logs' }]
From the Mongoose docs: "Populated paths are no longer set to their original _id , their value is replaced with the mongoose document returned from the database by performing a separate query before returning the results." In other words, in your query user.logs will be the logs document for each user. It will contain all the properties, in your case logTitle, createdOn, and postedBy.
Sending user.logs as json from the server is as easy as: res.json(user.logs). So your query can look like this:
const userReadLogs = function (req, res) {
if (req.params && req.params.userid) {
User1
.findById(req.params.userid)
.populate('logs')
.exec((err, user) => {
if (!user) { }); // shortened
return;
} else if (err) {
return; // shortened
}
res.status(200).json(user.logs)
});
} else { }); //
}
};
I hope this makes it a little bit clearer!