Managing.env like files is a means of preventing hard-coded credentials and separating environments.

It is good to implement multiple.env files, e.g..env.production,.env.development in Flutter app.

Then add some code beforedotenv.load can do environments separation:

// main.dart...voidmain()async{constenvironment=String.fromEnvironment('ENV',defaultValue:'development');awaitdotenv.load(fileName:'.env.$environment');...

Then run command likeflutter build web --dart-define ENV=production to spin it up.

But, here is a pitfall. In my practical learning, a file starts with dot. could cause 404 issue:

So, according tothis suggestion, we'd better use "dot" instead of ".".

1. Rename.env.production,.env.development files todotenv.production,dotenv.development

2. Update assets settings

3. Updatedotenv.load logic

// main.dart...voidmain()async{constenvironment=String.fromEnvironment('ENV',defaultValue:'development');awaitdotenv.load(fileName:'dotenv.$environment');...

4. Update.gitignore file

5. After building, delete unnecessarydotenv.* files inbuild > web > assets

In this case,dotenv.development is not necessary, so delete it to prevent potential sensitive data leaking.