how to insert all data to firebase before remove data from firebase by using callback method?

Question

i have built one system like shopping cart using js and firebase as database, after the transaction is success, i have to store the data from "Mycart" node to the "package history", also after finish insert all data to package history node, i need to delete the data from my cart node. the problem that i face is, the data is remove before i insert to database. there some logic error that i face. here the code.

deleteNode(updateHistory); // after the transaction is success 

function updateHistory() {
    var database = firebase.database();
    var ref = database.ref("mycart/" + uid);
    ref.on('value', gotData, errData);
}

function gotData(data) {
    // code to insert to PurchaseHistory
}

function error(err) {
    //
}

function deleteNode() {
    updateHistory();
    var database = firebase.database();
    var refremove = database.ref("mycart/" + uid);
    refremove.remove();
}

Answer 1

function gotData(data){
   dataRef.set("I'm writing data", function(error) {
     if (error) {
       alert("Data could not be saved." + error);
     } else {
       alert("Data saved successfully.");
       //remove here 
     }
   })
}