mongoose populate not populating the required field

Question

I have tried for several days trying to populate the users document with the bio data schema values.

I keep getting only the user data and not a combination of both schemas.

the following are the codes i have been working with.

These are the models:

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

this is the mongoose plugin

    const passportLocalMongoose = require('passport-local-mongoose')

the user Schema

    const UserSchema = new Schema({
         email: { type: String, unique: true, required: true},
         bios: {
             type: mongoose.Schema.Types.ObjectId,
             ref: 'Bio'
         },
         username: String,
         level: String,
         resetPasswordToken: String,
         resetPasswordExpires: Date
       });

The bio data Schema

    const BioSchema = new Schema({
         address: String,
         age: Number,
         gender: String,
         user: {
             type: mongoose.Schema.Types.ObjectId,
             ref: 'User'
         },
       });

using the plugin

    UserSchema.plugin(passportLocalMongoose, {usernameField: 'email'})

modelling the Schemas

    const User = mongoose.model('User', UserSchema, 'user');
       const Bio = mongoose.model('Bio', BioSchema, 'bio');
      module.exports =   {User, Bio}

These are the controllers:

    const {User, Bio} = require('../models/users');
    
       module.exports = {  

the user signup callback function

    signup: async (req, res, next)=>{
                   await User.register(new User(req.body), req.body.password).then(user=>{
                     req.login(user, function(err){
                        if(err) return next(err);
                          })

the bio data callback function

   postUserDetails: async (req, res, next)=>{
             const newBio = new Bio({
               address: req.body.address,
               age: req.body.age,
               gender: req.body.gender,
             })
             await newBio.save().then(result=>{
               console.log(result)
               res.redirect('/')
             }).catch(err=>{
               console.log(err)})
           },

get request populate callback function

    getUserDetails: async(req, res, next)=>{
          await User.findOne(_req.params._id).populate("bios").then(result=> res.json(result)).catch(err=> console.log(err))
        },
       } 

I am not getting the populated field, bios. I'm only getting the user data in return.

Somebody please help.

Answer 1

just try findOne({}) with {}

getUserDetails: async(req, res, next)=>{
      await User.findOne({_req.params._id}).populate("bios").then(result=> res.json(result)).catch(err=> console.log(err))
    },
   } 

or findById() without {}

getUserDetails: async(req, res, next)=>{
      await User.findById(_req.params._id).populate("bios").then(result=> res.json(result)).catch(err=> console.log(err))

Answer 2

Does your user document (one which you are querying in last snippet) has a bios value set and if it does, is there a bio document with that exact _id value?