how to save excel file converted to base64 in directory with xlsx?

Question

I am trying to save an excel file that I get from a post as base64, this conversion is done in my view, once I convert it, I try to save it with the xlsx library, this file is saving fine but when opening the file, it does not contain nothing. Can someone help me, in knowing what I am doing wrong?

my following code is:

private async getCurp(req: Request, res: Response) {

var datos = [];
let arrayusers = {};
const {
  curp
} = req.body;

const newCurp = new CurpModel({
  curp
});
const path = "C:\\Miroute"
var bufferFile = Buffer.from(curp, "base64");
const data = XLSX.read(bufferFile, { type: 'buffer' })
XLSX.writeFile(data, "excel.xls");
try {
  return Ok<CurpType>(res, newCurp);
}
catch (error) {
  console.log(error);
  return ServerError(res);
}

In my component I convert my excel file to base64 in this way, iam using react

    handleFileChange = e => {
    let idCardBase64 = '';
    this.getBase64(e.target.files[0], (result) => {
         idCardBase64 = result;
        console.log(idCardBase64)
         this.setState({
            file: idCardBase64,
          })
         
    });
  }

  getBase64(file, cb) {
    let reader = new FileReader();
    reader.readAsDataURL(file);
    reader.onload = function () {
        cb(reader.result)
    };
    reader.onerror = function (error) {
        console.log('Error: ', error);
    };
}

Please can someone help me?

Answer 1

My solution: I had not realized that my input parameter had a different name so it was undefined, the code looked like this:

    private async getCurp(req: Request, res:Response){

    var datos = [];
    let arrayusers = {};
    const {
      file
    } = req.body;
    const newCurp = new CurpModel({
      file
    });


    const bufferExcel = Buffer.from(newCurp.file.toString().replace("data:application/vnd.openxmlformats-officedocument.spreadsheetml.sheet;base64", ""),'base64');
    const workbook = XLSX.read(bufferExcel, { type: 'buffer' });
    const sheetNamesList = workbook.SheetNames;

    // parse excel data to json
    const excelData = XLSX.utils.sheet_to_json(workbook.Sheets[sheetNamesList[0]]);
    console.log(excelData);


    try{
    return Ok<CurpType>(res, newCurp);
    }
    catch(error){
        console.log(error);
        return ServerError(res);
    }
}