Env<T> class

A generic configuration property accessor for environment variables.

The Env<T> class provides a strongly-typed way to fetch environment variables at runtime. You can specify a key and an optional default value. If the environment variable is missing and no default is set, an InvalidArgumentException is thrown.

It can also be used as an annotation to inject environment variables into fields.

Example

void main() {
  // Fetch a required environment variable.
  final apiUrl = Env<String>('API_URL').value();

  // Fetch an environment variable with a default fallback.
  final timeout = Env<int>('TIMEOUT', defaultValue: 30).value();

  // Gracefully handle missing values without throwing.
  final optionalVar = Env<String>('OPTIONAL_VAR').valueOrNull();

  print('API URL: $apiUrl');
  print('Timeout: $timeout');
  print('Optional: $optionalVar');
}