从‘mssql’导入sql；console.log(sql)；//返回未定义的

Question

我正在尝试用Server在Nest.js中创建CRUD。我已安装下列套件：

mssql https://www.npmjs.com/package/mssql

@types/mssql https://www.npmjs.com/package/@types/mssql

我已经创建了一个服务database.service.ts，其中有以下代码：

import { Injectable } from '@nestjs/common';
import sql from 'mssql';

@Injectable()
export class DatabaseService {
  config = {
    user: 'mssql',
    password: 'password',
    server: 'localhost',
    database: 'atm',
    options: {
      encrypt: true,
      trustServerCertificate: true,
    },
  };

  async getPool() {
    console.log('SQL obj', JSON.stringify(sql));
    const pool = await sql.connect(this.config);
    return pool;
  }
}

在app.controller.ts中，我有以下内容：

import { DatabaseService } from './database/database.service';
import { Controller, Get } from '@nestjs/common';

@Controller()
export class AppController {
  constructor(private db: DatabaseService) {}

  @Get()
  getHello() {
    this.db.getPool().then((pool) => {
      pool
        .request()
        .query('SELECT 1')
        .then((res) => {
          return res;
        });
    });
  }
}

然后运行npm run start并使用Postman向端口3000发出以下GET请求：

​

​

如您所见，我没有得到任何响应，而且我的Nest.js服务器也崩溃了。

​

​

完整日志：

> cajero-backend@0.0.1 start C:\Users\carlo\Desktop\cajero\backend\cajero-backend
> nest start

[Nest] 11944  - 09/10/2021 16:11:32     LOG [NestFactory] Starting Nest application...
[Nest] 11944  - 09/10/2021 16:11:32     LOG [InstanceLoader] AppModule dependencies initialized +29ms
[Nest] 11944  - 09/10/2021 16:11:32     LOG [RoutesResolver] AppController {/}: +7ms
[Nest] 11944  - 09/10/2021 16:11:32     LOG [RouterExplorer] Mapped {/, GET} route +2ms
[Nest] 11944  - 09/10/2021 16:11:32     LOG [NestApplication] Nest application successfully started +1ms
SQL obj undefined
(node:11944) UnhandledPromiseRejectionWarning: TypeError: Cannot read property 'connect' of undefined
    at DatabaseService.getPool (C:\Users\carlo\Desktop\cajero\backend\cajero-backend\src\database\database.service.ts:19:28)
    at AppController.getHello (C:\Users\carlo\Desktop\cajero\backend\cajero-backend\src\app.controller.ts:15:13)
    at C:\Users\carlo\Desktop\cajero\backend\cajero-backend\node_modules\@nestjs\core\router\router-execution-context.js:38:29
    at InterceptorsConsumer.intercept (C:\Users\carlo\Desktop\cajero\backend\cajero-backend\node_modules\@nestjs\core\interceptors\interceptors-consumer.js:11:20)
    at C:\Users\carlo\Desktop\cajero\backend\cajero-backend\node_modules\@nestjs\core\router\router-execution-context.js:46:60
    at C:\Users\carlo\Desktop\cajero\backend\cajero-backend\node_modules\@nestjs\core\router\router-proxy.js:9:23
    at Layer.handle [as handle_request] (C:\Users\carlo\Desktop\cajero\backend\cajero-backend\node_modules\express\lib\router\layer.js:95:5)
    at next (C:\Users\carlo\Desktop\cajero\backend\cajero-backend\node_modules\express\lib\router\route.js:137:13)
    at Route.dispatch (C:\Users\carlo\Desktop\cajero\backend\cajero-backend\node_modules\express\lib\router\route.js:112:3)
    at Layer.handle [as handle_request] (C:\Users\carlo\Desktop\cajero\backend\cajero-backend\node_modules\express\lib\router\layer.js:95:5)
(Use `node --trace-warnings ...` to show where the warning was created)
(node:11944) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag `--unhandled-rejections=strict` (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 2)
(node:11944) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

吸引我注意的是，sql是未定义的 in database.service.ts，如何解决这个问题？我做错了什么？

Answer 1

我刚修好了！

我在"esModuleInterop": true,中添加了tsconfig.json，问题解决了。不知道为什么。

Answer 2

试试import * as sql from 'mssql';