javascript - Nestjs 无法解决依赖关系

Question

无法弄清楚我的代码有什么问题。 (我是 nestjs 的新手，我试图通过将一些应用程序传递给它来学习它)。控制台日志说:

Nest can't resolve dependencies of the UrlsAfipService (?). Please make sure that the argument at index [0] is available in the ApiModule context.

UrlsAfipService

import { Injectable } from '@nestjs/common';
import { AfipUrls } from './urls'

@Injectable()
export class UrlsAfipService {

  constructor(
    private readonly afipUrls: AfipUrls,
  ) {}

  getWSAA () {
    return this.afipUrls.homo().wsaa; // <- change to prod() for production
  }

  getService (service: string) {
    return this.afipUrls.homo().service.replace('{service}', service)
  }
}

AfipUrls

export class AfipUrls {
    homo() {
      return {
        wsaa: 'https://url.com',
        service: 'https://url.com'
      }
    }

    prod() {
      return {
        wsaa: 'url.com',
        service: 'url.com'
      }
    }
}

ApiModule

import { Module } from '@nestjs/common';
import { ApiController } from './api.controller';
import { UrlsAfipService } from './urls-afip.service'
import { WsaaService } from './wsaa.service'
import { DescribeService } from './describe.service';

@Module({
  controllers: [ApiController],
  providers: [UrlsAfipService, WsaaService, DescribeService]
})

export class ApiModule {}

应用模块

import { Module } from '@nestjs/common';

import { ApiModule } from './api/api.module';

import { AppController } from './app.controller';
import { AppService } from './app.service';

@Module({
  imports: [ApiModule],
  controllers: [AppController],
  providers: [AppService],
})

export class AppModule {}

Answer 1

您已将 AfipUrls 声明为 UrlsAfipService 的依赖项，但它未在任何模块中提供。

因此，您必须将 AfipUrls 添加到 ApiModule 的 providers 数组中。然后就可以注入(inject)了。

providers: [UrlsAfipService, WsaaService, DescribeService, AfipUrls]
//                                                         ^^^^^^^^

---

但请注意，代码库中的编码环境特定值可能是一种代码味道。考虑创建一个 ConfigService 来封装环境特定变量，这些变量是使用 dotenv 从环境变量或 .env 文件中读取的。看这个answer获取更多信息。