Sequelize virtual field or virtual column.

user.model.js

module.exports = (sequelize, DataTypes) => {
  return sequelize.define('users', {
    id: {
      autoIncrement: true,
      type: DataTypes.INTEGER(5),
      allowNull: false,
      primaryKey: true
    },
    firstname: {
      type: DataTypes.STRING(50),
      allowNull: true
    },
    lastname: {
      type: DataTypes.STRING(50),
      allowNull: true
    },
    email: {
      type: DataTypes.STRING(50),
      allowNull: true
    },
    profileImg: {
      type: DataTypes.STRING(100),
      allowNull: true,
    },
    imageUrl: {
      type: DataTypes.VIRTUAL,
      get() {
        return this.profileImgPath ? `localhost:8000/images/${this.profileImg}` : null;
      },
    }
  }, {
    sequelize,
    tableName: 'users',
  });
};