chore: further cleanup of .env files, documented how to use .env.local in todo app's readme

Author: Christiaan Landman

demos/react-native-supabase-group-chat/.env

@@ -1,5 +1,4 @@
-# Copy this template: `cp .env.template .env`
-# Edit .env and enter your Supabase and PowerSync project details.
+# Replace the credentials below with you Supabase, PowerSync and Expo project details.
 EXPO_PUBLIC_SUPABASE_URL=https://foo.supabase.co
 EXPO_PUBLIC_SUPABASE_ANON_KEY=foo
 EXPO_PUBLIC_POWERSYNC_URL=https://foo.powersync.journeyapps.com

demos/react-native-supabase-todolist/.env

@@ -1,6 +1,6 @@
-# Edit and enter your Supabase and PowerSync project details.
+# Replace the credentials below with you Supabase, PowerSync and Expo project details.
 EXPO_PUBLIC_SUPABASE_URL=https://foo.supabase.co
 EXPO_PUBLIC_SUPABASE_ANON_KEY=foo
-EXPO_PUBLIC_SUPABASE_BUCKET= // Optional. Only required when syncing attachments and using Supabase Storage. See packages/powersync-attachments.
+EXPO_PUBLIC_SUPABASE_BUCKET= # Optional. Only required when syncing attachments and using Supabase Storage. See packages/powersync-attachments.
 EXPO_PUBLIC_POWERSYNC_URL=https://foo.powersync.journeyapps.com
 EXPO_PUBLIC_EAS_PROJECT_ID=foo # Optional. Only required when using EAS.

demos/react-native-supabase-todolist/README.md

@@ -37,9 +37,16 @@ bucket_definitions:
 
 ## Configure The App
 Replace the necessary credentials in the [.env](./.env) file.
+Generally, the `.env` file is used for storing common environment variables shared across all instances of the application, while `.env.local` is for overriding or providing environment-specific configurations, particularly for local development.
+As `.env.local` is normally not checked into source control (this project has a git-ignore rule), you can copy `.env`, name it `.env.local`, and then configure as needed.
 
+### EAS Build configuration
 Take note that you will need an Expo account if you want to use EAS for your builds, the Expo project ID should then also be configured in the environment file.
 
+For secret/sensitive environment variables which shouldn't be checked into source control, you can configure them as EAS secrets. They can be added via either the Expo website or the EAS CLI, both are explained [here](https://docs.expo.dev/build-reference/variables/#using-secrets-in-environment-variables).
+
+General information on defining environment variables with Expo can be found here [here](https://docs.expo.dev/build-reference/variables/#can-eas-build-use-env-files).
+
 ## Run the App
 
 Install the dependencies, including the React Native SDK:

demos/react-native-supabase-todolist/app.config.ts

@@ -3,9 +3,9 @@ import { type ExpoConfig } from "expo/config";
 import { config as dotenvConfig} from 'dotenv'
 import { resolve } from 'path'
 
-// EAS doesn't load values from `.env` by default when considering the `app.config.ts` file
+// EAS doesn't load values from `.env` by default when consider the `app.config`
 dotenvConfig({
-  path: resolve(__dirname, '.env') || resolve(__dirname, '.env.local')
+  path: resolve(__dirname, '.env')
 })
 
 const projectId = process.env.EXPO_PUBLIC_EAS_PROJECT_ID;