whenOrNull<TResult extends Object?> method

@optionalTypeArgs TResult? whenOrNull<TResult extends Object?>(TResult? $default(String $type, @FilterablePreferenceConverter() FilterablePreference follow, @FilterablePreferenceConverter() FilterablePreference like, @FilterablePreferenceConverter() FilterablePreference likeViaRepost, @FilterablePreferenceConverter() FilterablePreference mention, @FilterablePreferenceConverter() FilterablePreference quote, @FilterablePreferenceConverter() FilterablePreference reply, @FilterablePreferenceConverter() FilterablePreference repost, @FilterablePreferenceConverter() FilterablePreference repostViaRepost, @PreferenceConverter() Preference starterpackJoined, @PreferenceConverter() Preference subscribedPost, @PreferenceConverter() Preference unverified, @PreferenceConverter() Preference verified, Map<String, dynamic>? $unknown,)?)

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 $type, @FilterablePreferenceConverter()  FilterablePreference follow, @FilterablePreferenceConverter()  FilterablePreference like, @FilterablePreferenceConverter()  FilterablePreference likeViaRepost, @FilterablePreferenceConverter()  FilterablePreference mention, @FilterablePreferenceConverter()  FilterablePreference quote, @FilterablePreferenceConverter()  FilterablePreference reply, @FilterablePreferenceConverter()  FilterablePreference repost, @FilterablePreferenceConverter()  FilterablePreference repostViaRepost, @PreferenceConverter()  Preference starterpackJoined, @PreferenceConverter()  Preference subscribedPost, @PreferenceConverter()  Preference unverified, @PreferenceConverter()  Preference verified,  Map<String, dynamic>? $unknown)?  $default,) {final _that = this;
switch (_that) {
case _Preferences() when $default != null:
return $default(_that.$type,_that.follow,_that.like,_that.likeViaRepost,_that.mention,_that.quote,_that.reply,_that.repost,_that.repostViaRepost,_that.starterpackJoined,_that.subscribedPost,_that.unverified,_that.verified,_that.$unknown);case _:
  return null;

}
}