Add new row with post request to Google Sheet using Google App Script

insert.gs

const doPost = (request = {}) => {
    try{
  var sheetApp = SpreadsheetApp.openByUrl("YoursharedSheetLINK");
     var sheet = sheetApp.getSheets()[0];
  
   
  
  const { parameter, postData: { contents, type } = {} } = request;
  const { source } = parameter;

  if (type === 'application/json') {
    const jsonData = JSON.parse(contents);
    var textdata = JSON.stringify(jsonData)
      sheet.appendRow([textdata])
    
    
  }

   return ContentService
          .createTextOutput(JSON.stringify({"result":"success"}))
          .setMimeType(ContentService.MimeType.JSON);

} catch(e){
    // if error return this
    return ContentService
          .createTextOutput(JSON.stringify({"result":"error", "error": e}))
          .setMimeType(ContentService.MimeType.JSON);
  } 
};