Retrieve random ID key generated by Firebase?

Question

How do I retrieve the random ID key generated by Firebase?

For example, if I have this:

    users
    │
    ├──── KT4NTZTzFduj3DNLQgg
    │     │
    │     ├────  uid: "7ZLldIsRu3NQMOb6"
    │     └────  username: "John"
    │
    │
    └──── TO39dsjk2wREF34kmcs // I want this
          │
          ├────  uid: "455klfmckjsnenk2sxkm2"
          └────  username: "Micheal"

I want to get the key which holds a username with value equal to Micheal.

firebase.database()
    .ref('users')
    .orderByChild("username")
    .equalTo("Micheal")
    .once("value", 
            function (snapshot) {
                // what should I write here ??
            });

Possible duplicate of [In Firebase when using push() How do I pull the unique ID](http://stackoverflow.com/questions/16637035/in-firebase-when-using-push-how-do-i-pull-the-unique-id) — dafyk, Oct 02 '16 at 18:18

score 0 · Accepted Answer · answered Oct 02 '16 at 20:16

The query will return a snapshot containing the matching children under users.

You can enumerate the children and obtain the matching child's key via the child snapshot's key property:

firebase.database().ref("users")
  .orderByChild("username")
  .equalTo("Micheal")
  .once("value", function (snapshot) {

    var key;

    snapshot.forEach(function (childSnapshot) {
      key = childSnapshot.key;
      return true; // Cancel further enumeration.
    });

    if (key) {
      console.log("Found user: " + key);
    } else {
      console.log("User not found.");
    }
  });

Retrieve random ID key generated by Firebase?

1 Answers1