Facebook API返回null，如何在Javascript中跳过它

如果没有返回空值，这段代码工作得很好。但我在测试期间注意到，如果任何值为null，那么它会抛出错误并中断脚本的其余部分

如果为null，我如何跳过该值，或将其设置为其他值

function fqlQuery(){
                FB.api('/me', function(response) {
                     var query = FB.Data.query('SELECT uid, first_name, last_name, email, sex, pic_square, timezone, birthday_date, current_location FROM user WHERE uid = me()', response.id);
                     query.wait(function(rows) {
                        fb_uid = rows[0].uid;
                        first_name = rows[0].first_name;
                        last_name = rows[0].last_name;
                        sex = rows[0].sex;
                        email = rows[0].email;
                        fb_pic_square = rows[0].pic_square;
                        timezone = rows[0].timezone;
                        birthday_date = rows[0].birthday_date;
                        current_city = rows[0].current_location.city;
                        current_country = rows[0].current_location.country;
                        $.ajax({
                            type: "POST",
                            url: "postdb.php",
                            data: "first_name=" + first_name + "&last_name=" + last_name + "&email=" + email + "&fb_uid=" + fb_uid + "&sex=" + sex + "&fb_pic_square=" + fb_pic_square + "&timezone=" + timezone + "&birthday_date=" + birthday_date + "&current_city=" + current_city + "&current_country=" + current_country,

   success: function(msg){
     alert( "Data Saved: " + msg );
   }

                        });



                     });

                });

提前谢谢

var foo = rows[0].foo || "";

如果

行[0]，将返回
”
（空字符串）。foo

为空。

我这样修复了它

if(rows[0].current_location != null){
  current_city = rows[0].current_location.city || "";
  current_country = rows[0].current_location.country || "";
}

---

我刚试过你的建议。仍然得到同样的结果。行[0]。当前_位置为空[在此错误上中断]当前_城市=行[0]。当前_位置。城市| |“”；如果当前位置不为空，则仅访问当前位置.city。