localhost_oa_based/src/common/entity/common.entity.ts

import { ApiHideProperty, ApiProperty } from '@nestjs/swagger';
import { Exclude } from 'class-transformer';
import {
  BaseEntity,
  Column,
  CreateDateColumn,
  PrimaryGeneratedColumn,
  UpdateDateColumn,
  VirtualColumn
} from 'typeorm';

// 如果觉得前端转换时间太麻烦，并且不考虑通用性的话，可以在服务端进行转换，eg: @UpdateDateColumn({ name: 'updated_at', transformer })
// const transformer: ValueTransformer = {
//   to(value) {
//     return value
//   },
//   from(value) {
//     return dayjs(value).format('YYYY-MM-DD HH:mm:ss')
//   },
// }

export abstract class CommonEntity extends BaseEntity {
  @PrimaryGeneratedColumn()
  id: number;

  @CreateDateColumn({ name: 'created_at' })
  createdAt: Date;

  @UpdateDateColumn({ name: 'updated_at' })
  updatedAt: Date;
}

export abstract class CompleteEntity extends CommonEntity {
  @ApiHideProperty()
  @Exclude()
  @Column({ name: 'create_by', update: false, comment: '创建者' })
  createBy: number;

  @ApiHideProperty()
  @Exclude()
  @Column({ name: 'update_by', comment: '更新者' })
  updateBy: number;

  /**
   * 不会保存到数据库中的虚拟列，数据量大时可能会有性能问题，有性能要求请考虑在 service 层手动实现
   * @see https://typeorm.io/decorator-reference#virtualcolumn
   */
  @ApiProperty({ description: '创建者' })
  @VirtualColumn({ query: alias => `SELECT username FROM sys_user WHERE id = ${alias}.create_by` })
  creator: string;

  @ApiProperty({ description: '更新者' })
  @VirtualColumn({ query: alias => `SELECT username FROM sys_user WHERE id = ${alias}.update_by` })
  updater: string;
}