whenOrNull<TResult extends Object?> method

@optionalTypeArgs TResult? whenOrNull<TResult extends Object?>(TResult? $default(String tag, @JsonKey.new(name: 'selector') XrayStringList selectors, StrategyConfig? strategy, String? fallbackTag,)?)

A variant of when that fallback to returning null

It is equivalent to doing:

switch (sealedClass) {
  case Subclass(:final field):
    return ...;
  case _:
    return null;
}

Implementation

@optionalTypeArgs
TResult? whenOrNull<TResult extends Object?>(
  TResult? Function(
          String tag,
          @JsonKey(name: 'selector') XrayStringList selectors,
          StrategyConfig? strategy,
          String? fallbackTag)?
      $default,
) {
  final _that = this;
  switch (_that) {
    case _BalancingRule() when $default != null:
      return $default(
          _that.tag, _that.selectors, _that.strategy, _that.fallbackTag);
    case _:
      return null;
  }
}