Concepts,,,,(සංකල්ප)

 Firebase Nodejs requests are Asyncronus .Which means, in the follwing code block I need to check order users exhist before set user. But the user order insert fucntion written second will fire before validation finished .Developer need to careful on this when firebase adopted.     for(var user in users) {                                              f irebase.database().ref("users"); users.once("value", function(snapshot) {                                      var temp= snapshot.exists();                                                             if (temp) {             ...