CODEWITHSUNDEEP
javascriptfirebasefirebase-realtime-database
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Reputation: 497

Remove Object in Firebase? (JavaScript)

I'm trying to loop through an object in my app and delete old messages after there are 30 messages already in the Database. Here is my code so far:

var ref1 = firebase.database().ref("chatRooms/" + rm + "/messages");
var query = ref1.orderByChild("time");

query.once("value").then(function(l) {
    l.forEach(function(d) {
      ref1.once("value").then(function(snapshot1) {
      var ast = snapshot1.numChildren(); // Getting the number of children
      console.log(ast);
      if (ast > 29) {
        d.remove();

      }
    });
  });
});

The only problem is that I receive the following error for each one:

SCRIPT438: Object doesn't support property or method 'remove'.

If anyone knows how to fix this, or knows of an alternative, I'd appreciate it!

Upvotes: 1

Views: 4713

Answers (1)

Frank van Puffelen
Frank van Puffelen

Reputation: 600120

Your d is a DataSnapshot, which represents the value at a given location at some specific time. It cannot be removed directly.

But you can look up the location that the value is from and call remove() there:

d.ref.remove();

Full working (and simplified) snippet:

function deleteMessages(maxCount) {
  root.once("value").then(function(snapshot) {
    var count = 0;
    snapshot.forEach(function(child) {
      count++;
      if (count > maxCount) {
        console.log('Removing child '+child.key);
        child.ref.remove();
      }
    });
    console.log(count, snapshot.numChildren());
  });

}

deleteMessages(29);

Live code sample: http://jsbin.com/tepate/edit?js,console

Upvotes: 1

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