Try Catch

AnotherUser.js

const mongoose = require('mongoose');
const bcrypt = require('bcryptjs');
const jwt = require('jsonwebtoken');
const UserProfile = require('./userProfile.js');

var userSchema = new mongoose.Schema({
  name: {
    type: 'string',
    required: true
  },
  email: {
    type: 'string',
    unique: true,
    required: true,
    downcase: true
  },
  password: {
    type: 'string',
    required: true
  },
  isVerified: {
    type: 'boolean',
    default: false
  }
});

userSchema.path("email").validate(email => {
  var emailRegex = /^([\w-\.]+@([\w-]+\.)+[\w-]{2,4})?$/;
  return emailRegex.test(email);
}, "Not a valid email!");

userSchema.pre("save", async function(next) {
 let salt = await bcrypt.genSalt(10);
 let hashedPassword = await bcrypt.hash(this.password, salt);
 this.password = hashedPassword;
 next();
});

userSchema.post("save", function(next) {
  let id = this._id
  UserProfile.create({
    user: id
  });
});

var User = mongoose.model('User', userSchema);

User.register = async function(data) {
  return new Promise(async function(resolve, reject) {
    if (!data.password) {
      return reject([400, "Password is blank"]);
    };

    if (data.password != data.password_confirmation) {
      return reject([400, "Password doesn't match!"]);
    };

    delete data.password_confirmation

    try {
      let user = await User.create(data);
      resolve([201, {
        _id: user._id,
        name: user.name,
        email: user.email
      }]);
    }

    catch (err) {
      reject([422, err]);
    }
  });
}

User.authenticate = async function(data) {
  return new Promise(async function(resolve, reject) {
    if (!data.password) {
      return reject([400, "No password!"]);
    }

    let user = await User.findOne({
      email: data.email
    }).select(['_id','email','password']);

    if (!user) {
      return reject([401, "Email hasn't registered yet!"]);
    }

    let isCorrect = await bcrypt.compare(data.password, user.password);

    if (!isCorrect) {
      return reject([401, "Password incorrect!"]);
    }

    let token = jwt.sign({ _id: user._id }, process.env.JWT_SIGNATURE);
    resolve([200, token]);
  });
}

module.exports = User;