whenOrNull<TResult extends Object?> method

  1. @optionalTypeArgs
TResult? whenOrNull<TResult extends Object?>(
  1. TResult? $default(
    1. String title,
    2. String? titleLong,
    3. String isbn,
    4. String isbn13,
    5. String? deweyDecimal,
    6. String? binding,
    7. String? publisher,
    8. String? language,
    9. DateTime? datePublished,
    10. String? edition,
    11. int? pages,
    12. String? dimensions,
    13. String? overview,
    14. String? image,
    15. double? msrp,
    16. String? excerpt,
    17. String? synopsys,
    18. List<String?>? authors,
    19. List<String>? subjects,
    20. List<String>? reviews,
    21. List<Merchant>? prices,
    22. List<String>? related,
    )?
)

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 title, @JsonKey(name: 'title_long')  String? titleLong,  String isbn,  String isbn13, @JsonKey(name: 'dewey_decimal')  String? deweyDecimal,  String? binding,  String? publisher,  String? language, @_DateConverter()@JsonKey(name: 'date_published')  DateTime? datePublished,  String? edition,  int? pages,  String? dimensions,  String? overview,  String? image, @_MsrpConverter()  double? msrp,  String? excerpt,  String? synopsys,  List<String?>? authors,  List<String>? subjects,  List<String>? reviews,  List<Merchant>? prices,  List<String>? related)?  $default,) {final _that = this;
switch (_that) {
case _Book() when $default != null:
return $default(_that.title,_that.titleLong,_that.isbn,_that.isbn13,_that.deweyDecimal,_that.binding,_that.publisher,_that.language,_that.datePublished,_that.edition,_that.pages,_that.dimensions,_that.overview,_that.image,_that.msrp,_that.excerpt,_that.synopsys,_that.authors,_that.subjects,_that.reviews,_that.prices,_that.related);case _:
  return null;

}
}