基于另一个没有装饰器的域级 class 创建 TypeORM 实体

Question

I would like to separate between domain-level, pure business logic entities - and the TypeORM / any other framework bindings.

For example, right now an Address looks like this in order to bind it with TypeORM:

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

  @Column({ nullable: true })
  firstName: string;

  @Column({ nullable: true })
  lastName: string;

  @Column({ nullable: true })
  streetAddress1: string;
}

I would rather have a pure data class such as

export class Address {
  id: number;
  firstName: string;
  lastName: string;
  streetAddress1: string;
}

And define the TypeORM binding from another place, to separate concerns and not have my core business logic know anything about TypeORM (Or any other framework I might migrate to).

How would you approach this in a clean way, without creating a duplicate entity class just for TypeORM? Any clever way to use the TypeScript type system to extend the existing pure entity class and decorate it for TypeORM DB binding?

Answer 1

One option might be to create a type from your TypeORM model, I've renamed it AddressEntity :

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

  @Column({ nullable: true })
  firstName: string;

  @Column({ nullable: true })
  lastName: string;

  @Column({ nullable: true })
  streetAddress1: string;
}

...

type Address = typeof AddressEntity

const address: Address = {
   // ... typescript requires that you define these fields
}