@clients = src/domains/clients
@clientsEnities = src/adapters/typeorm/entities/clients
@adapters = src/adapters

import { Contact } from './Contact';
export interface Client {
  id: number;
  title: string;
  contacts?: Contact[];
}

import { Client } from './Client';
export enum ContactType {
  PHONE = 'phone',
  EMAIL = 'email',
}
export interface Contact {
  client?: Client;
  type: ContactType;
  value: string;
}

import { Column, Entity, OneToMany, PrimaryGeneratedColumn } from 'typeorm';
import { Client as ClientModel } from '@clients/models/Client';
import { Contact } from './Contact';
@Entity({ name: 'clients' })
export class Client implements ClientModel {
  @PrimaryGeneratedColumn()
  id: number;
  @Column()
  title: string;
  @OneToMany((_type) => Contact, (contact) => contact.client)
  contacts?: Contact[];
}

import { Column, Entity, ManyToOne, PrimaryGeneratedColumn } from 'typeorm';
import { Contact as ContactModel, ContactType } from '@clients/models/Contact';
import { Client } from './Client';
@Entity({ name: 'contacts' })
export class Contact implements ContactModel {
  @PrimaryGeneratedColumn()
  id: number;
  @Column({ type: 'string' })
  type: ContactType;
  @Column()
  value: string;
  @ManyToOne((_type) => Client, (client) => client.contacts, { nullable: false })
  client?: Client;
}

import { Repository } from 'typeorm';
import { Client as ClientModel } from '@clients/models/Client';
import { Client } from '@clientsEnities/Client';
export async function  createClient(repo: Repository<Client>, clientData: ClientModel) {
  const client = await repo.save(clientData);
  return client;
}

import { Connection } from 'typeorm';
import { Client } from '@clientsEnities/Client';
import { Client as ClientModel } from '@clients/models/Client';
import { createClient } from './methods/createClient';
export class Clients {
  protected _connection: Connection;
  constructor(connection: Connection) {
    if (!connection) {
      throw new Error('No connection!');
    }
    this._connection = connection;
  }
  protected getRepository<T>(Entity: any) {
    return this._connection.getRepository<T>(Entity);
  }
  protected getTreeRepository<T>(Entity: any) {
    return this._connection.getTreeRepository<T>(Entity);
  }
  public async createClient(clientData: ClientModel) {
    const repo = this.getRepository<Client>(Client);
    const client = await createClient(repo, clientData);
    return client;
  }
}

import { Client as ClientModel } from '@clients/models/Client';
import { Clients } from '@clients';
import { db } from '@adapters/typeorm'; // Я складываю TypeORM соединения в объект db
export function createClient(clientData: ClientModel) {
  const clients = new ClientService(db.connection)
  const client = await clients.createClient(clientData)
  return  client
}