问转换为函数时无法编译代码

EN

  public createData(data:Data):Observable<any>{
    console.log('contacting server at '+this.API_URL +this.NEW_DATA_URL +" with data "+data+ " with httpOptions "+httpOptions.withCredentials + ","+httpOptions.headers );

let newData = new Data(data)    
    let body = JSON.stringify(newQuestion); 
//I WANT TO MOVE THE CODE BELOW INTO A FUNCTION BUT AM GETTING COMPILATION ERROR
    this.loaderService.show();
    return this.http.post(this.NEW_QUESTION_URL,body,httpOptions)
      .pipe(tap(response => { 
        let httpEvent = <HttpEvent<any>>response;
        if(httpEvent.type === HttpEventType.Response)
        {
          console.log('response from backend service:', response);

          return result;
        }
        else {
          console.log("not an http response")
          return response;
        }
      })
      ,catchError(this.handleError)
        ,finalize(()=> this.loaderService.hide())); //error handler if Observable fails

  }

private sendMessage(url:string, body:any,httpOptions:any){
    this.loaderService.show();
    return this.http.post(url,body,httpOptions)
      .pipe(tap(response => { 

          let httpEvent = <HttpEvent<any>>response; //ERROR HERE - 'ArrayBuffer' cannot be converted to type 'HttpEvent<any>'.
          if(httpEvent.type === HttpEventType.Response)
          {
            console.log('response from backend service:', response);

            let result = <HttpResponse<any>>response;

            return result;
          }
          else {
            console.log("not an http response")
            return response;
          }
        })
        ,catchError(this.handleError)
        ,finalize(()=> this.loaderService.hide())); //error handler if Observable fails
    }

const httpOptions = {
  headers: new HttpHeaders({ 'Content-Type': 'application/json' }),
  withCredentials: true, 
observe: 'response' as 'response', 
  responseType: 'json' 
};


let observable:Observable<HttpEvent<any>> = this.http.post(url,body,httpOptions)
    return observable.pipe(tap((httpEvent:HttpEvent<any>) => {....}

ERROR in src/app/web-to-backend-interface.service.ts(80,71): error TS2345: Argument of type '{ headers: HttpHeaders; withCredentials: boolean; observe: "response"; responseType: string; }' is not assignable to parameter of type '{ headers?: HttpHeaders | { [header: string]: string | string[]; }; observe?: "body"; params?: Ht...'.
  Types of property 'observe' are incompatible.
    Type '"response"' is not assignable to type '"body"'.
src/app/web-to-backend-interface.service.ts(111,52): error TS2345: Argument of type '{ headers: HttpHeaders; withCredentials: boolean; observe: "response"; responseType: string; }' is not assignable to parameter of type '{ headers?: HttpHeaders | { [header: string]: string | string[]; }; observe?: "body"; params?: Ht...'.
  Types of property 'observe' are incompatible.
    Type '"response"' is not assignable to type '"body"'.
src/app/web-to-backend-interface.service.ts(195,73): error TS2345: Argument of type '{ headers: HttpHeaders; withCredentials: boolean; observe: "response"; responseType: string; }' is not assignable to parameter of type '{ headers?: HttpHeaders | { [header: string]: string | string[]; }; observe?: "body"; params?: Ht...'.
src/app/web-to-backend-interface.service.ts(215,72): error TS2345: Argument of type '{ headers: HttpHeaders; withCredentials: boolean; observe: "response"; responseType: string; }' is not assignable to parameter of type '{ headers?: HttpHeaders | { [header: string]: string | string[]; }; observe?: "body"; params?: Ht...'.
src/app/web-to-backend-interface.service.ts(250,54): error TS2345: Argument of type '{ headers: HttpHeaders; withCredentials: boolean; observe: "response"; responseType: string; }' is not assignable to parameter of type '{ headers?: HttpHeaders | { [header: string]: string | string[]; }; observe?: "body"; params?: Ht...'.
src/app/web-to-backend-interface.service.ts(290,9): error TS2322: Type 'Observable<ArrayBuffer>' is not assignable to type 'Observable<HttpEvent<any>>'.
  Type 'ArrayBuffer' is not assignable to type 'HttpEvent<any>'.
    Type 'ArrayBuffer' is not assignable to type 'HttpUserEvent<any>'.
      Property 'type' is missing in type 'ArrayBuffer'.
src/app/web-to-backend-interface.service.ts(296,59): error TS2552: Cannot find name 'response'. Did you mean 'Response'?