Usage of Sequelize transaction

You might remark this line, if (!options.transaction) throw new Error('Missing transaction.');, in the hashPassword method decorated with the @BeforeCreate. As said before, Sequelize provides a strong support of the transaction. So for each action or process of action, you can use a transaction. To use the Sequelize transaction, take a look at the following example of a UserService.

@Injectable()
export class UserService implements IUserService {
    constructor(@Inject('UserRepository') private readonly UserRepository: typeof User,
                @Inject('SequelizeInstance') private readonly sequelizeInstance) { }
    ...
}

We have injected both the model and the Sequelize instance that we talked about earlier in this chapter.

To use a transaction to wrap some access to the database, you can do the following:

public async create(user: IUser): Promise<User> {
    return await this.sequelizeInstance.transaction(async...