whenOrNull<TResult extends Object?> method

  1. @optionalTypeArgs
TResult? whenOrNull<TResult extends Object?>(
  1. TResult? $default(
    1. int? maxSelectable,
    2. bool requireAdjacency,
    3. bool preventSingleSeatGaps,
    4. bool restrictToSingleCategory,
    )?
)

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( int? maxSelectable,  bool requireAdjacency,  bool preventSingleSeatGaps,  bool restrictToSingleCategory)?  $default,) {final _that = this;
switch (_that) {
case _SelectionRules() when $default != null:
return $default(_that.maxSelectable,_that.requireAdjacency,_that.preventSingleSeatGaps,_that.restrictToSingleCategory);case _:
  return null;

}
}