onlyOnce: true fails to work on onChildAdded and onChildRemoved

[marcusx2]

Operating System

macOS

Browser Version

Safari 16.5.2

Firebase SDK Version

10.7.0

Firebase SDK Product:

Database

Describe your project's tooling

index.html with source tag. Just javascript.

Describe the problem

The onlyOnce option fails to work on onChildAdded and onChildRemoved. I couldn't test onChildMoved though.

Steps and code to reproduce issue

onChildRemoved(ref(db, "posts"), snapshot => {
    console.log("==onChildRemoved==");
    console.log(snapshot.val());
}, error => console.error(error), { onlyOnce : true });

onValue(ref(db, "posts"), snapshot => {
    console.log("==onValue==");
    console.log(snapshot.val());
}, error => console.error(error), { onlyOnce: true });

onChildMoved(ref(db, "posts"), snapshot => {
    console.log("==onChildMoved==");
    console.log(snapshot.val());
}, error => console.error(error), { onlyOnce: true });

onChildChanged(ref(db, "posts"), snapshot => {
    console.log("==onChildChanged==");
    console.log(snapshot.val());
}, error => console.error(error), { onlyOnce: true });

onChildAdded(ref(db, "posts"), snapshot => {
    console.log("==onChildAdded==");
    console.log(snapshot.val());
}, error => console.error(error), { onlyOnce: true });

set(ref(db), {
    "posts": {
        "ts-functions": {
            "metrics": {
                "views": 1200000,
                 "likes": 251000,
                  "shares": 100,
             },
             "title": "Why you should use TypeScript for writing Cloud Functions",
             "author": "Doug",
       },
       "android-arch-3": {
           "metrics": {
           "views": 900000,
           "likes": 117000,
           "shares": 144,
        },
        "title": "Using Android Architecture Components with Firebase Realtime Database (Part 3)",
        "author": "Doug",
      }
}});

By running this example, onChildAdded gets triggered twice. Then, you can just delete the data from the database and the onChildRemoved will trigger twice. I don't know how to test the onChildMoved. Maybe onChildMoved just triggers once, maybe not, but it's worth looking into as well. onValue and onChildChanged triggers just once as expected.