title: TypeError: this.http.post(...).map is not a function after update angular 5 to angular 6
body: <p>I meet some problem  about rxjs6 after update Angular 5 to Angular 6:</p>
  
  <pre><code>TypeError: this.http.post(...).map is not a function
  
  error TS2339: Property 'map' does not exist on type 'Observable&lt;Object&gt;'.
  
  TypeError: rxjs__WEBPACK_IMPORTED_MODULE_1__.Observable.of is not a function
  </code></pre>
  
  <p>I have tried some methods , like :</p>
  
  <p>add this import to service.ts</p>
  
  <blockquote>
    <p><strong>import { map } from 'rxjs/operators';</strong></p>
    
    <p><strong>change http.post().pipe(map(res => {...}))</strong></p>
  </blockquote>
  
  <p>However , all of thoes are not work for me .</p>
  
  <p>My enviroment follow as:</p>
  
  <pre><code> "@angular/cli": "^6.0.3"
   "rxjs": "^6.2.0"
   "rxjs-compat": "^6.2.0"
  </code></pre>
  
  <p><strong>code show as below</strong>
       Service.ts</p>
  
  <pre><code>import { Injectable } from '@angular/core';
  import {environment} from '../../environments/environment';
  import {HttpClient} from '@angular/common/http';
  import {StorageService} from '../services/storage.service';
  
  @Injectable()
  export class VariationService {
  ip = environment.url.management;
  constructor(private http: HttpClient,
              private storageService: StorageService) { }
  getFlowChart(status?) {
      status = status ? status : '';
      let token = this.storageService.getToken('token');
      return this.http.post(
          `${this.ip}/workflow`,
          {
              'access_token': token,
              'type': 'adjustment_workflow_get',
              'data': {
                  'status': status
              }
          }
      ).map((res: Response) =&gt; {
        if ( res['errcode'] !== '00000') {
          return [];
        }
        return res['datas'];
      });
  }
  }
  </code></pre>
  
  <p>Another problem typscript file</p>
  
  <pre><code>import {Injectable} from '@angular/core';
  import { PreloadingStrategy, Route } from '@angular/router';
  import { Observable } from 'rxjs';
  
  @Injectable()
  export class SelectivePreloadingStrategy implements PreloadingStrategy {
    preloadedModules: string[] = [];
    preload(route: Route, load: () =&gt; Observable&lt;any&gt;): Observable&lt;any&gt; {
      if (route.data &amp;&amp; route.data['preload']) {
        this.preloadedModules.push(route.path);
       return load();
      } else {
        return Observable.of(null);
      }
    }
  }
  </code></pre>