boolean method

bool boolean(String name, { required bool orElse, })

The value parsed as a boolean.

true, 1, yes and on are true; false, 0, no and off are false, each case-insensitively. Anything else throws rather than being quietly read as false — a feature flag set to "maybe" should be a deployment error, not a silent no.

Implementation

bool boolean(String name, {required bool orElse}) {
  final value = this[name]?.toLowerCase();
  if (value == null) {
    return orElse;
  }

  return switch (value) {
    'true' || '1' || 'yes' || 'on' => true,
    'false' || '0' || 'no' || 'off' => false,
    _ => throw StateError(
        'Environment variable "$name" is "$value", which is not a boolean.',
      ),
  };
}