/// src/entities/user-id.ts
export class UserId {
  constructor(public readonly value: string) {}
}

/// src/entities/post-id.ts
export class PostId {
  constructor(public readonly value: string) {}
}

/// src/entities/user.entity.ts
import { Column, Entity, PrimaryColumn } from "typeorm";
import { UserId } from "./user-id";

@Entity()
export class User {
  @PrimaryColumn({
    type: "text",
    transformer: {
      from(value: string) {
        return new UserId(value);
      },
      to(id: UserId) {
        return id.value;
      },
    },
  })
  id!: UserId;

  @Column()
  name!: string;
}

/// src/entities/post.entity.ts
import { Column, Entity, ManyToOne, PrimaryColumn } from "typeorm";
import { PostId } from "./post-id";
import { UserId } from "./user-id";
import { User } from "./user.entity";

@Entity()
export class Post {
  @PrimaryColumn({
    type: "text",
    transformer: {
      from(value: string) {
        return new PostId(value);
      },
      to(id: PostId) {
        return id.value;
      },
    },
  })
  id!: PostId;

  @ManyToOne(() => User)
  author?: User;

  @Column({
    type: "text",
    transformer: {
      from(value: string) {
        return new UserId(value);
      },
      to(id: UserId) {
        return id.value;
      },
    },
  })
  authorId!: UserId;
}

/// src/main.ts
import { dataSource } from "./data-source";
import { PostId } from "./entities/post-id";
import { Post } from "./entities/post.entity";
import { UserId } from "./entities/user-id";
import { User } from "./entities/user.entity";

const USER_ID = new UserId("abcd-1234");
const POST_ID = new PostId("first");

async function insertData() {
  const user = dataSource.manager.create(User, {
    id: USER_ID,
    name: "Tom",
  });
  await dataSource.manager.save(user);

  const post = dataSource.manager.create(Post, {
    authorId: USER_ID,
    id: POST_ID,
  });
  await dataSource.manager.save(post); // <-- this fails
}


async function main() {
  await dataSource.initialize();
  await insertData();
}

main().catch((e) => console.error(e));