User model and mongoose

User.js

const bcrypt = require('bcrypt-nodejs');
const mongoose = require('mongoose');

const userSchema = new mongoose.Schema({
    email: {
      type: String,
      required: true,
      unique: true,
    },
    password: String,
});

/**
 * Password hash middleware.
 */
userSchema.pre('save', function save(next) {
    const user = this;
    if (!user.isModified('password')) { return next(); }
    bcrypt.genSalt(10, (err, salt) => {
      if (err) { return next(err); }
      bcrypt.hash(user.password, salt, null, (err, hash) => {
        if (err) { return next(err); }
        user.password = hash;
        next();
      });
    });
  });
  
  /**
   * Helper method for validating user's password.
   */
  userSchema.methods.comparePassword = function comparePassword(candidatePassword) {
    return new Promise((resolve, reject) => {
      bcrypt.compare(candidatePassword, this.password, (err, isMatch) => {
        if (err) { reject(err); }
        resolve(isMatch);
      });
    });
  };

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

module.exports = User;