How can I read .xlsx row using javascript and convert it to .json file

I have some trouble on on converting my code to .json file.

document.getElementById('button').addEventListener("click", () => {
XLSX.utils.json_to_sheet(data, 'out.xlsx');
if(selectedFile){
    let fileReader = new FileReader();
    fileReader.readAsBinaryString(selectedFile);
    fileReader.onload = (event)=>{
     let data = event.target.result;
     let workbook = XLSX.read(data,{type:"binary"});
     console.log(workbook);
     workbook.SheetNames.forEach(sheet => {
          let rowObject = XLSX.utils.sheet_to_row_object_array(workbook.Sheets[sheet]);
          console.log(rowObject);
          document.getElementById("jsondata").innerHTML = JSON.stringify(rowObject,undefined,4)
     });
    }
}

});

Also I need to read xlsx file per row and convert it as a .json file
Thanks for the help!