Can I prevent Firebase set() from overwriting existing data?

Question

If I do this, all is good with my itemRef:

itemRef.child('appreciates').set(newFlag);
itemRef.child('id').set(newId);

other properties of itemRef remain BUT child_changed is called twice

If I do this:

itemRef.set({appreciates:newFlag,id:newId});

child_changed is called only once but my other properties are destroyed. Is there a workaround besides the clumsy one of repopulating the entire reference object?

Thanks,

Tim

Answer 1

Now .update takes care of it, you can change existing data or add new one without affecting the rest of data you already had there.

In this example, I use this function to set a product as sold, the product has other variables with data and may or may not have sold or sellingTime but it doesn't matter cos if it doesn't exist will create them and if it does, will update the data

var sellingProduct = function(id){
 dataBase.ref('product/'+id).update({
   sold:true,
   sellingTime: Date.now(),

 }).then (function(){
   alert ('your product is flaged as sold')

 }).catch(function(error){
    alert ('problem while flaging to sold '+ error)
 })

}

Answer 2

Though you can use update, you can also use set with merge option set to true:

itemRef.set({ appreciates:newFlag, id:newId }, { merge: true });

This will create a new document if it doesn't exists and update the existing if it does.