攔截器程式碼如下：

import {Injectable} from '@angular/core';
import {HttpEvent, HttpInterceptor, HttpHandler, HttpRequest, HttpResponse} from '@angular/common/http';
import {Observable} from 'rxjs/Observable';
import {ErrorObservable} from 'rxjs/observable/ErrorObservable';
import {catchError} from 'rxjs/operators';
import {mergeMap} from 'rxjs/operators';
@Injectable()
export class InterceptorService implements HttpInterceptor {
  constructor(private messageService: MessageService, private translate: TranslateService) {}

  intercept(req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
    return next.handle(req).pipe(mergeMap((event: any) => {
        const err = event.body && event.body.err;
        if (err) {
          switch (err) {
            case -1:
              // 在提示框中展示錯誤訊息
              break;
            default:
              break;
          }
        }
        if (event instanceof HttpResponse && event.status !== 200) {
          return ErrorObservable.create(event);
        }
        return Observable.create(observer => observer.next(event)); // 請求成功返回響應
      }),
      catchError((res: HttpResponse<any>) => {   // 請求失敗處理
        this.messageService.clear();
        switch (res.status) {
          case 500:
            // 提示請求超時
            break;
          default:
            // 提示網路錯誤
        }
        return ErrorObservable.create(event);
      }));
  }
}
 

在對應module中註冊提供商：

import {HTTP_INTERCEPTORS, HttpClientModule} from '@angular/common/http';

@NgModule({
    providers: [
    {provide: HTTP_INTERCEPTORS, useClass: InterceptorService, multi: true}
    ]
})
export class SharedModule {
}

如果所有模組都需要用攔截器的話，可以在shareModule中進行註冊(如果在app.module中進行註冊的話，只會在專案首次載入時有效)。