How should I write typeorm entity and find code?

Question

I created two tables. One is a user and the other is a friend table that has relationships between users.

The friend table was created to resolve the many-to-many relationship between users.

How can I create a typeorm entity and retrieve data in the form below?

{
    "id": "1000014",
    "name": "fu",
    "address": aasd,
    "createdTime": "2023-03-09T01:00:00.000Z",
    "updatedTime": "2023-03-09T09:11:18.243Z",
    "friends": [
      {
        "id": "5",
        "name": "kaka",
        "address": asdf,
        "createdTime": "2023-03-09T01:00:00.000Z",
        "updatedTime": "2023-03-09T09:11:18.243Z"
      },
      {
        "id": "6",
        "name": "lod",
        "address": asdf,
        "createdTime": "2023-03-09T01:00:00.000Z",
        "updatedTime": "2023-03-09T09:11:18.243Z"
      },
      {
        "id": "7",
        "name": "asdf",
        "address": asdf,
        "createdTime": "2023-03-09T01:00:00.000Z",
        "updatedTime": "2023-03-09T09:11:18.243Z"
      },
      {
        "id": "8",
        "name": "qwer",
        "address": asdf,
        "createdTime": "2023-03-09T01:00:00.000Z",
        "updatedTime": "2023-03-09T09:11:18.243Z"
      },
      {
        "id": "9",
 
        "name": "qwer",
        "address": dasfsdf,
        "createdTime": "2023-03-09T01:00:00.000Z",
        "updatedTime": "2023-03-09T09:11:18.243Z"
      }
    ]
  },
  {
    "id": "1000120",
    "name": "asdvv",
    "address": asdf,
    "createdTime": "2023-03-08T15:00:00.000Z",
    "updatedTime": "2023-03-09T09:11:18.243Z",
    "friends": [
      {

Answer 1

Assuming you have already created the necessary tables in your database, you can create two entities in TypeORM for the User and Friend tables.

User Entity:

import { Entity, PrimaryGeneratedColumn, Column, ManyToMany, JoinTable } from 'typeorm';
import { Friend } from './friend.entity';

@Entity()
export class User {
  @PrimaryGeneratedColumn()
  id: number;

  @Column()
  name: string;

  @Column()
  address: string;

  @Column()
  createdTime: Date;

  @Column()
  updatedTime: Date;

  @ManyToMany(() => Friend)
  @JoinTable({
    name: 'user_friend',
    joinColumn: { name: 'user_id', referencedColumnName: 'id' },
    inverseJoinColumn: { name: 'friend_id', referencedColumnName: 'id' },
  })
  friends: Friend[];
}

Friend Entity:

import { Entity, PrimaryGeneratedColumn, Column } from 'typeorm';

@Entity()
export class Friend {
  @PrimaryGeneratedColumn()
  id: number;

  @Column()
  name: string;

  @Column()
  address: string;

  @Column()
  createdTime: Date;

  @Column()
  updatedTime: Date;
}

After creating the entities, you can use TypeORM to retrieve the data in the required format using a query like this:

import { getRepository } from 'typeorm';
import { User } from './entities/user.entity';

async function getUsersWithFriends(): Promise<User[]> {
  const userRepository = getRepository(User);
  const users = await userRepository.find({ relations: ['friends'] });
  return users;
}