Azure Function call in SPFx

private async promoteNews(pageName: string, pageType:string, newsstatus: string, siteUrl: string): Promise<string> {
    var functionUrl : string = "<azure function url>"
    const requestHeaders: Headers = new Headers();
    requestHeaders.append("Content-type", "application/json");
    requestHeaders.append("Cache-Control", "no-cache");
  
    const postOptions : RequestInit = {
     headers: requestHeaders,
     body: `{\r\n    siteURL: '${siteUrl}',\r\n    pageType: '${pageType}', \r\n    pageName: '${pageName}', \r\n    pageStatus: 'edit', \r\n    newsStatus: '${newsstatus}'\r\n}`,
     method: "POST"
    };
    
    let responseText: string = "";
    let createPageStatus: string = "";
    console.log('Wait started');
    await fetch(functionUrl, postOptions).then((response) => {
          console.log('Response returned');
          if (response.ok) {
            return response.json()
          }
          else
          {
              var errMsg = "Error detected while updating site page. Server response wasn't OK ";
              console.log(errMsg);
              createPageStatus = "failed";
          } 
        }).then((responseJSON: JSON) => {
          responseText = JSON.stringify(responseJSON).trim();
          console.log(responseText);
          if(responseText.toLowerCase().indexOf("uccess") > 0)
              {
                console.log("setting");
                createPageStatus = "success";
              }
          if(responseText.toLowerCase().indexOf("rror") > 0)
              {
                console.log("errored");
                createPageStatus = "error";
              }
        }
      ).catch ((response: any) => {
        let errMsg: string = `WARNING - error when calling URL ${functionUrl}. Error = ${response.message}`;
        console.log(errMsg);
        createPageStatus = "failed";
      });
      console.log("Wait finished");
      return createPageStatus;
  }

responseText.toLowerCase().indexOf("uccess") > 0
responseText.toLowerCase().indexOf("rror") > 0

what the fuck?