How to manage dynamic path in app to Firebase data

Question

I have data in my Firebase that looks something like this (this is a Javascript-based web app):

bids
    400
        1
            50.00
        2
                   


        

Answer 1

Since you're building your query like this:

dataRef.child('bids').child(auction).child(lotno).on(...

You will have to create attach a new listener (and turn off the existing listener) every time one of the action or lotno variables changes.

It sounds like there can only be a single current lot at a time, which might make it more useful to model that into your data model:

bids
    400
        1
            50.00
        2
            60.00
    401
        1
            55.00
        current
            65.00

Then once the bidding on the current lot has finished, you can "retire" it to its proper lotnumber slot and have the next lot become the current. With a data structure like this, your listener for an auction could always be watching current:

dataRef.child('bids').child(auction).child('current').on(...