Saving the Aggregate with Sequelize

Inside the save method for the SequelizeUserRepo that implements IUserRepo, we use a Mapper in order to convert a User into the shape needed to persist it to Sequelize, as per the Sequelize docs.

// users/repos/implementations/sequelizeUserRepo.ts

import { UserMap } from '../mappers/userMap'

export class SequelizeUserRepo implements IUserRepo {
  private models: any;

  constructor(models: any) {
    this.models = models;

  async exists(userEmail: UserEmail): Promise<boolean> {

  async save(user: User): Promise<void> {
    const UserModel = this.models.BaseUser;
    const exists = await this.exists(;

    if (!exists) {
      // Create a JSON representation { username, password, userId, email }
      const rawSequelizeUser = await UserMap.toPersistence(user);
      // Save the user model
      await UserModel.create(rawSequelizeUser);
    } else {
      // Update logic


Note: Notice that we import UserMap directly? Normally, we wouldn't do that. But UserMap is a stable dependency.

Here's what the UserMap looks like. Pay particular attention to the toPersistence method where we take in a User and convert…

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