whenOrNull<TResult extends Object?> method

  1. @optionalTypeArgs
TResult? whenOrNull<TResult extends Object?>(
  1. TResult? $default(
    1. DNSOutboundRuleAction action,
    2. XrayPortList? qType,
    3. XrayStringList? domain,
    4. int? rCode,
    )?
)

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(DNSOutboundRuleAction action, XrayPortList? qType,
          XrayStringList? domain, int? rCode)?
      $default,
) {
  final _that = this;
  switch (_that) {
    case _DNSOutboundRuleConfig() when $default != null:
      return $default(_that.action, _that.qType, _that.domain, _that.rCode);
    case _:
      return null;
  }
}