let shopId = element.get('shop_id')           let shopName = ''           resultShop = new AV.Query('shop').equalTo('shop_id', shopId)           resultShop.find().then((shop) => {             shop.forEach((element) => {               shopName = element.get('shop_name')             })           })           console.log(shopName) element.get('shop_name')可以取得到值， 但shopName 的输出为空？是为什么？