How to parse an excel file?

Question

Node.js

Hello I want to read excel file cell value and using
xlsx https://www.npmjs.com/package/xlsx
Wrote

function excel2json(buffer) {
    function getFirstDigitPosition(str) {
      let i = 0;
      for (; str[i] < '0' || str[i] > '9'; i++);
      return i == str.length ? -1 : i;
    }

    let workbook = XLSX.read(buffer, { type: "buffer" });
    let sheetNamesList = workbook.SheetNames;
    sheetNamesList.forEach(function (sheetName) {
      let worksheet = workbook.Sheets[sheetName];
      for (let cellName in worksheet) {
        if (cellName[0] === "!") continue;

        let numberPosition = getFirstDigitPosition(cellName);
        let colName = cellName.substring(0, numberPosition);
        let rowNumber = parseInt(cellName.substring(numberPosition));
        let cellValue = worksheet[cellName].v;
        console.log("\n" + cellName + ":" + cellValue); //A1:�� ࡱ �????????????????>? ?�� вместо нормальной строчки

      }
    });
  }

Everything works, but the value from the cell is not read correctly, which could go wrong