nestjs 中的 httpSerive 中的 rxjs 用法请教, 在线等

rxjs 新手上路, 在使用 nestjs 中用到了 HttpModule, 是基于 rxjs 封装的一个 axios, 在用的过程中不熟悉 rxjs 的用法, 官网来来回回看了好久了, 不得方法结果达不到预期, 请教一下大佬正确的姿势. 谢谢

代码

import { HttpModule } from '@nestjs/axios';

@Module({
  imports: [
    HttpModule.register({
      baseURL: 'https://jsonplaceholder.typicode.com',
    }),
  ],
  controllers: [AppController],
  providers: [AppService],
})
export class AppModule {}

  // controller
  
  @Get('/')
  getHello() {
    return this.appService.getHello();
  }

// service

import { Injectable } from '@nestjs/common';
import { HttpService } from '@nestjs/axios';
import { map } from 'rxjs';

@Injectable()
export class AppService {
  constructor(private httpService: HttpService) {}

  getHello() {
    return this.httpService.get('/users').pipe(
      map((res) => res.data),
      map((data) => {
        return data.map((user) => {
          user.name = user.name.toUpperCase();
          user.posts = [];
          if (user.id % 2 === 0) {
          // 当符合条件时,需要获取到对应的 posts 并 push 给当前的 user
            this.httpService.get('/posts/' + user.id).pipe(
              map((post) => {
                user.posts.push(post.data);
              }),
            );
          }
          return user;
        });
      }),
      map((res) => {
        return res;
      }),
    );
  }
}

预期

id 为奇数时 posts 应该为空, id 为偶数时 posts 应该有获取到的 post

[
  {
    "id": 1,
    "name": "LEANNE GRAHAM",
    "username": "Bret",
    "email": "Sincere@april.biz",
    "address": {
      "street": "Kulas Light",
      "suite": "Apt. 556",
      "city": "Gwenborough",
      "zipcode": "92998-3874",
      "geo": { "lat": "-37.3159", "lng": "81.1496" }
    },
    "phone": "1-770-736-8031 x56442",
    "website": "hildegard.org",
    "company": {
      "name": "Romaguera-Crona",
      "catchPhrase": "Multi-layered client-server neural-net",
      "bs": "harness real-time e-markets"
    },
    "posts": []
  },
  {
    "id": 2,
    "name": "ERVIN HOWELL",
    "username": "Antonette",
    "email": "Shanna@melissa.tv",
    "address": {
      "street": "Victor Plains",
      "suite": "Suite 879",
      "city": "Wisokyburgh",
      "zipcode": "90566-7771",
      "geo": { "lat": "-43.9509", "lng": "-34.4618" }
    },
    "phone": "010-692-6593 x09125",
    "website": "anastasia.net",
    "company": {
      "name": "Deckow-Crist",
      "catchPhrase": "Proactive didactic contingency",
      "bs": "synergize scalable supply-chains"
    },
    "posts": ['postObject1']
  }
]

现状

所有 user 的 posts 都为空

版本环境

  "dependencies": {
    "@nestjs/axios": "^0.0.7",
    "@nestjs/common": "^8.0.0",
    "@nestjs/core": "^8.0.0",
    "@nestjs/platform-express": "^8.0.0",
    "axios": "^0.26.1",
    "reflect-metadata": "^0.1.13",
    "rimraf": "^3.0.2",
    "rxjs": "^7.2.0"
  },

额外的信息

这里写了一个基于 promise 实现需求的例子, 希望大佬提供一个切换成 rxjs 实现的例子点击这里 codePen