title: Angular 4 Http Interceptor: next.handle(...).do is not a function
body: <p>I created this HTTPInterceptor to be able to better handle http errors, it was working well before I did a git pull and ran npm install. </p>
  
  <p>This is my code:</p>
  
  <pre><code>import {Injectable} from '@angular/core';
  import {HttpEvent, HttpInterceptor, HttpHandler, HttpRequest, HttpResponse} from '@angular/common/http';
  import {Observable} from "rxjs";
  import {ToasterService} from "angular2-toaster";
  
  @Injectable()
  export class GobaeInterceptor implements HttpInterceptor {
      constructor(private toasterService: ToasterService){
      }
      intercept(req: HttpRequest&lt;any&gt;, next: HttpHandler): Observable&lt;HttpEvent&lt;any&gt;&gt; {
          return next.handle(req)
              .do(event =&gt; {
                  if (event instanceof HttpResponse) {
                      let response = event.body;
                      if(response.Error){
                          this.toasterService.pop('error', 'Error '+response.Code, response.Message);
                      }
                  }
              });
      }
  }
  </code></pre>
  
  <p>And this is the error I get:</p>
  
  <blockquote>
    <p>TypeError: next.handle(...).do is not a function
        at GobaeInterceptor.webpackJsonp.../../../../../src/app/services/gobae.interceptor.ts.GobaeInterceptor.intercept
    (gobae.interceptor.ts:12)
        at HttpInterceptorHandler.webpackJsonp.../../../common/@angular/common/http.es5.js.HttpInterceptorHandler.handle
    (</p>
  </blockquote>
  
  <p>Did something that can affect my code changed lately? what can I do now to "catch" the http response on my interceptor?</p>