title: NodeJs Mongoose findById returns empty doc with status true
body: <p>I'm trying to implement CRUD operations using MEAN stack. I'm facing a problem on getting user by Id. It's showing the status true but it returns an empty document.</p>
  
  <p>This is my model:</p>
  
  <pre><code>const userSchema = new mongoose.Schema({
      fullName: {
          type: String,
          required: 'Full name can\'t be empty '
      },
      userName: {
          type: String,
          required: 'user name can\'t be empty ',
          unique: true
      },
      email: {
          type: String,
          required: 'email can\'t be empty ',
          unique: true
      });
  
  mongoose.model('User', userSchema);
  </code></pre>
  
  <p>in my controller:</p>
  
  <pre><code>const mongoose = require('mongoose');
  const passport = require('passport');
  var ObjectId = require('mongoose').Types.ObjectId;
  const User = mongoose.model('User');
  
  module.exports.getuser = (req, res, next) =&gt; {
      if(!ObjectId.isValid(req.params.id))
          return res.status(400).send(`No record with given id : ${req.params.id}`);
  
      User.findById(req.params.id, (err, user) =&gt; {
          if(!err){ res.status(200).json({status: true, user}); }
          else{ console.log('Error in retriving User :' + JSON.stringify(err, undefined, 2)); }
      });    
  }
  </code></pre>
  
  <p>This is the route:</p>
  
  <pre><code>router.get('/:id', jwtHelper.verifyJwtToken, ctrlUser.getuser);
  </code></pre>
  
  <p>while checking in the postman I'm getting status: true but it returns a blank document.
  I'm not getting what's going on anyone please help. 
  Thanks in advance!!</p>