whenOrNull<TResult extends Object?> method

@optionalTypeArgs TResult? whenOrNull<TResult extends Object?>(TResult? $default(int id, ProposalData params)?)

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 id,  ProposalData params)?  $default,) {final _that = this;
switch (_that) {
case _SessionProposal() when $default != null:
return $default(_that.id,_that.params);case _:
  return null;

}
}