Accessing a schema inside a schema using Express Router and MongoDG - node.js

Question

I'm trying to create a route where it takes in a parameter for a username and then displays that users information. Only thing is, the username is in the user schema from when the user signs up. The profile schema references the user schema. How do I use the username parameter in the findOne call to display the users profile data?
User schema:
const UserSchema = new Schema({
username: {
type: String,
required: true
},
email: {
type: String,
required: true
},
password: {
type: String,
required: true
},
date: {
type: Date,
default: Date.now
}
});
module.exports = User = mongoose.model("users", UserSchema);
Profile schema:
const ProfileSchema = new Schema({
user: {
type: Schema.Types.ObjectId,
ref: "users"
},
name: {
type: String
},
image: {
type: String
},
bio: {
type: String
},
location: {
type: String
},
website: {
type: String
},
social: {
youtube: {
type: String
},
facebook: {
type: String
},
instagram: {
type: String
},
twitter: {
type: String
}
}
});
module.exports = User = mongoose.model("profile", ProfileSchema);
Route:
router.get("/user/:username", (req, res) => {
const errors = {};
Profile.findOne({ user: req.params.user.username })
.populate("user", "username")
.then(profile => {
if (!profile) {
errors.noprofile = "There is no profile for this user";
return res.status(404).json(errors);
}
res.json(profile);
})
.catch(err => res.status(404).json(err));
});

Answer 1

Please try this :
router.get("/user/:username", async (req, res) => {
const errors = {};
try {
const profile = await User.aggregate([
{ $match: { username: req.params.username } },
{ $lookup: { from: "profile", localField: "_id", foreignField: "user", as: "userProfile" } },
{ $project: { userProfile: { $arrayElemAt: ["$userProfile", 0] }, username: 1, _id:0 } }
]).exec();
if (!profile.length) {
errors.noprofile = "There is no profile for this user";
return res.status(404).json(errors);
}
res.json(profile[0]);
} catch (error) {
console.log('Error in retrieving user from DB ::', error);
return res.status(404);
}
})

Answer 2

Try using aggregate, firstly you check-in user table for getting details of a specific username then fetch the profile details as below using lookup, if no profile found after unwind the document will not be fetched and you can check on aggregate result's length as aggregate always return an array in result :
User.aggregate([
{$match:{ username: req.params.user.username }},
{$lookup:{from:"profile",localField:"_id",foreignField:"userId",as:"profileData"}},
{$unwind:"$profileData"},
{$project:{profileData:1,username:1}}
{$limit:1}
])
.then(profile => {
if (!profile.length) {
errors.noprofile = "There is no profile for this user";
return res.status(404).json(errors);
}
res.json(profile[0]);
})

Answer 3

You can do it in 2 steps.
Look for users containing username in userSchema, get it's id.
Then in promise, use that id to, look for profileSchema contains.
router.get("/user/:username", (req, res) => {
users.findOne({ username: req.params.username }).then(_user=>{
profile.findOne({ user: _user._id }).populate('user').then(_profile => {
res.json(_profile);
})
})
});
This code will look for username in userSchema and look for userSchema's id in profileSchema then returns profileSchema populated with user.