Facroty to create typeOrm repositories

repository-factory.ts

import {
  EntityManager,
  EntityMetadata,
  EntityTarget,
  QueryRunner,
  Repository,
  TreeRepository,
} from 'typeorm';
import { Injectable } from '@nestjs/common';

/**
 * Factory used to create different types of repositories.
 */

@Injectable()
export class RepositoryFactory {
  /**
   * Creates a repository.
   */
  create<T>(
    target: EntityTarget<T>,
    manager: EntityManager,
    metadata: EntityMetadata,
    queryRunner?: QueryRunner,
  ): Repository<T> {
    if (metadata.treeType) {
      const repository = new TreeRepository<T>(target, manager, queryRunner);
      Object.keys(metadata).forEach(
        (m) => (repository.metadata[m] = metadata[m]),
      );
      return repository;
    } else {
      const repository = new Repository<T>(target, manager, queryRunner);
      Object.keys(metadata).forEach(
        (m) => (repository.metadata[m] = metadata[m]),
      );
      return repository;
    }
  }
}