Section Intro

In this section, we’ll complete our eCommerce app and deploy it as a Flutter web demo using Firebase Hosting.

The last feature we need to implement is Product Reviews, so we can:

• see the average review score for each product, along with a list of reviews
• submit a new review or update an existing one

Along the way, we will:

• Check out a new starter project and highlight the latest changes
• Implement a ReviewsRepository class so we can read and write product reviews with Cloud Firestore
• Talk about aggregate queries such as COUNT, SUM, AVG
• Implement a Cloud Function trigger that calculates the average review score and writes it to Cloud Firestore, so the Flutter app can read it using realtime updates
• Build the Flutter web app in release mode and deploy it with Firebase Hosting
• Update the CORS policy for the Firebase Storage bucket, so the product images load correctly on Flutter web