如何提取Prisma Client扩展类型？拆分扩展时的类型定义难题

方法1：从原始Prisma Client类型中提取对应模型的扩展类型 #

直接从_prismaClient实例的类型里提取query.company的类型，完美匹配原扩展的约束：

// companyExtensions.ts
import { CompanyStatus, AccountLockedReason } from './path-to-enums';
import type { _prismaClient } from './prismaClient';

// 提取Prisma Client扩展参数中company模型的query扩展类型
type PrismaClientType = typeof _prismaClient;
type CompanyQueryExtensions = NonNullable<
  Parameters<PrismaClientType['$extends']>[0]['query']
>['company'];

export const companyExtensions: CompanyQueryExtensions = {
  update: async ({ args, query }) => {
    if (args.data?.status === CompanyStatus.DECLINED) {
      args.data.user = {
        update: {
          accountLocked: AccountLockedReason.COMPANY_DECLINED,
        },
      };
    }
    return query(args);
  },
};

方法2：使用Prisma内置的QueryExtension类型 #

利用Prisma提供的工具类型，直接指定目标模型和操作：

// companyExtensions.ts
import { CompanyStatus, AccountLockedReason } from './path-to-enums';
import type { Prisma } from '@prisma/client';
import type { QueryExtension } from '@prisma/client/runtime/library';

// 定义Company模型update操作的扩展类型
type CompanyUpdateExtension = QueryExtension<'update', 'company'>;

export const companyExtensions: {
  update: CompanyUpdateExtension
} = {
  update: async ({ args, query }) => {
    if (args.data?.status === CompanyStatus.DECLINED) {
      args.data.user = {
        update: {
          accountLocked: AccountLockedReason.COMPANY_DECLINED,
        },
      };
    }
    return query(args);
  },
};

注意事项 #

• 避免循环导入问题：可将_prismaClient的类型单独抽离到类型文件，或在prismaClient.ts中导出该类型
• 后续添加create/delete等操作时，只需在companyExtensions对象中补充对应方法，类型会自动匹配约束

内容的提问来源于stack exchange，提问作者j_d