SMSのコードを返すGAS

SMS_CODE.gs

function doGet() {
  const spreadsheet = SpreadsheetApp.getActiveSpreadsheet();
  const sheet = spreadsheet.getActiveSheet();
  const range = sheet.getRange("A2");
  const value = ('000000' + range.getValue()).slice(-6);
  const out = ContentService.createTextOutput();
  out.setMimeType(ContentService.MimeType.JSON);
  out.setContent(JSON.stringify({"code": value}));
  return out;
}