Calling method inside itselft

Ionic Framework ionic-v3
1

Hi, iam using cordova nfc plugin in my app, to read nfc tag, then i check if it is correct on the server and i navigate to next page, or activate reader again.My code in service(userService) looks like this:

public startReading(){
        return new Promise((resolve,reject)=>{
            nfc.readerMode(nfc.FLAG_READER_NFC_A,(tag)=>{
                nfc.disableReaderMode();
                resolve(this.transformTag(tag.id));
            },err=>{
                console.log(err);
                nfc.disableReaderMode();
                reject(err);
            });
        });
    }

and in my page i use it like this:

ionViewWillEnter(){
    console.log("nfcAktivaceLogin");
    this.platform.ready().then(()=>{
      this.userService.startReading().then((tagId)=>{
        console.log("tagid",tagId);
        this.uisLogin(tagId);
      });
    })
  }

uisLogin(tagID){
    let loading=this.loadingCtrl.create({
      spinner:'crescent'
    });
    loading.present();
    this.productService.loginEmployee(tagID).subscribe((data)=>{
      console.log("Výsledek",data);
      loading.dismiss();
      this.navCtrl.push(HomePage);
    }, err=>{
      loading.dismiss();
      this.userService.startReading().then((tagId)=>{
        console.log("tagid",tagId);
        this.uisLogin(tagId);
      });
      let alert = this.alertCtrl.create({
        title: err.message,
        buttons: ['OK']
      });
      alert.present();
    });
  }

In uisLogin Method, iam calling itself inside it, is it a problem? I kinda think that it isnt the best solution, but it seems to be working. Any ideas?