Ionic export to excel not working

I am new to ionic and when I try to export excel nothing is happening. I tried different things but they all lead back to the same result.

here is my code.

component.ts

export class HomePage implements OnInit {

  scannedResult: any[] = [];
  contentvisibility = 'show';
  displayedColumns = ['firstname', 'lastname', 'company', 'email'];

  scannedRsult1: any[] = [];
  base64result: string;

  constructor(private barcodeScanner: BarcodeScanner,  private plt: Platform, private fileOpener: FileOpener,
    private file: File, private socialSharing: SocialSharing) {
    this.storage.create();

    this.storage.get('item').then((res) => {
      if (res) {
        this.scannedResult = res;
        alert(this.scannedResult);
      }
    });
  }
  async ngOnInit() {

    await this.storage.create();
  }


  startScan() {
    this.barcodeScanner.scan().then(barcodeData => {
      console.log('Barcode data', barcodeData);

      this.scannedResult.push(JSON.parse(barcodeData.text));

      // this.setObject(barcodeData);

      this.storage.set('item', this.scannedResult)
        .then(
          () => {
            alert('Item Stored Success');
          },
          error => console.error('Error storing item', error)
        );

      return barcodeData;


    }).catch(err => {
      console.log('Error', err);
    });
  }



   createExcel() {
    const ws = XLSX.utils.json_to_sheet(this.scannedResult);
      // eslint-disable-next-line
    const wb = { Sheets: { 'data': ws }, SheetNames: ['data'] };
    const buffer = XLSX.write(wb, {
      bookType: 'xlsx',
      type: 'array'
    });

    
    const fileType = 'application/vnd.openxmlformats-officedocument.spreadsheetxml.sheet';
    const blob: Blob = new Blob([buffer], { type: fileType });

    this.convertFile(blob).subscribe(res=>{
      console.log(res);
    this.base64result = res;
    console.log(this.base64result);
    this.saveToPhone(this.base64result);
    }, err => {
              console.log(err);
    });
  }



    saveToPhone(buffer: any) {
    
    const fileType = 'application/vnd.openxmlformats-officedocument.spreadsheetxml.sheet';
    const fileName = 'Visitor_Data';
    const fileExtension = '.xlsx';
    const currentDate = new Date().toLocaleString().replace(/[,:\s\/]/g, '-');
    const name = `myFile-${currentDate}.xlsx`;
     console.log(name);


      //method one
      this.file.writeFile(this.file.dataDirectory, fileName + fileExtension, buffer, {replace: true}).then(res => {
      this.fileOpener.open(res.nativeURL, fileType);

   console.log(res);
       alert('excel file saved in phone');
      });

   // method two
      Filesystem.writeFile({
        path: name,
        data: buffer,
        directory: Directory.Documents,
        encoding: Encoding.UTF8

      });

  

  }

   //conver one
  convertFile(file : Blob) : Observable<string> {
    const result = new ReplaySubject<string>(1);
    const reader = new FileReader();
    reader.readAsBinaryString(file);
    reader.onload = (event) => result.next(btoa(event.target.result.toString()));
    return result;
  }

// convert two
   blobToBase64(blob: Blob): Observable<string> {
    return new Observable<string>(observer => {
      const reader = new FileReader();
      reader.onerror = observer.error;
      reader.onabort = observer.error;
      reader.onload = () => observer.next(reader.result as string);
      // reader.onloadend =  observer.complete.bind(observer);
      reader.readAsDataURL(blob);
  });

}

}

I tried it with the two methods I mentioned above but they failed to save the excel file to the device.