Sequelize User model in es6

User.js

import Sequelize from 'sequelize';

/**
 * A model class representing user resource
 *
 * @param {Sequelize} sequelize - Sequelize object
 * @param {Sequelize.DataTypes} DataTypes - A convinient object holding data types
 * @return {Sequelize.Model} - User model
 */
export default (sequelize, DataTypes) => {
  /** @type {Sequelize.Model} */
  const User = sequelize.define('User', {
    username: {
      type: DataTypes.STRING,
      allowNull: false,
      unique: true,
      validate: {
        is: /^[a-zA-Z0-9]+$/i,
      },
      set(val) {
        this.setDataValue('username', val.toLowerCase()); // convert to lowercase
      },
    },
    email: {
      type: DataTypes.STRING,
      allowNull: false,
      unique: true,
      validate: {
        isEmail: { msg: 'Must be a valid email address' },
      },
    },
    bio: DataTypes.STRING,
    image: DataTypes.STRING,
    hash: DataTypes.STRING,
    salt: DataTypes.STRING,
    createdAt: {
      type: DataTypes.DATE,
      defaultValue: sequelize.NOW,
    },
    updatedAt: {
      type: DataTypes.DATE,
      defaultValue: sequelize.NOW,
      onUpdate: sequelize.NOW,
    },
  });

  /**
   * User relationship
   *
   * @param {Sequelize.Model} models - Sequelize model (destructured)
   * @returns {void}
   */
  User.associate = (models) => {
    // association comes in here
  };
  return User;
};