Notes

In this section, we’re going to dive deeper into Cloud Firestore by learning how to add, update, or delete items from our shopping cart using Cloud Firestore.

As part of this, we’ll learn:

1. how to setup realtime listeners so that our UI rebuilds automatically when the data changes
2. how to model our data and calculate the shopping cart total efficiently by combining values from different documents
3. how to reduce costs by minimizing the number of reads and writes, as well as the storage and network bandwidth requirements of our app

These are all essential topics that you need to understand if you want to provide a good user experience while minimizing the cost of your Firebase bill.

And as usual, I’ll guide you through various important concepts using diagrams so that we always keep an eye on the big picture.

And by the end of this section, you should better understand how to identify issues that could lead to a big Firebase bill and how to fix them in your own apps.