Welcome Bot Telegram

function doPost(e) {
  var token = "xxxxxx";

  var stringJson = e.postData.getDataAsString();

  var updates = JSON.parse(stringJson);
  var chatid = updates.message.chat.id;
  if(isContainText(updates)) {
    var text = "Hello "+updates.message.from.first_name+", IPTV list link available on Pinned Post, please check!!!\n\n Before start please download our app here => https://bit.ly/3fgNqZy.\n\n How to use? Check tutorial here => https://t.me/tigeriptv/238";
  } else if(isContainNewMember(updates)){
    var text = "Hello "+updates.message.new_chat_member.first_name+" welcome to Vola Sports IPTV Telegram Group, before start please download our app here => https://bit.ly/3fgNqZy.\n\n How to use? Check tutorial here => https://t.me/tigeriptv/238";
  }
  var url = "https://api.telegram.org/bot"+token+"/sendMessage?chat_id="+encodeURIComponent(chatid)+"&text="+encodeURIComponent(text);
  var replay = UrlFetchApp.fetch(url);
}

function isContainText(updates) {
  if(updates.message.text == null){
    return false;
  } else {
    return true;
  }
}

function isContainNewMember(updates){
  if(updates.message.new_chat_member == null){
    return false;
  } else{
    return true;
  }
}