whenOrNull<TResult extends Object?> method

  1. @optionalTypeArgs
TResult? whenOrNull<TResult extends Object?>({
  1. TResult? success(
    1. T? item,
    2. RequestDetails details
    )?,
  2. TResult? failure(
    1. FailureReason reason,
    2. String message
    )?,
})

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( T? item,  RequestDetails details)?  success,TResult? Function( FailureReason reason,  String message)?  failure,}) {final _that = this;
switch (_that) {
case ReadSuccess() when success != null:
return success(_that.item,_that.details);case ReadFailure() when failure != null:
return failure(_that.reason,_that.message);case _:
  return null;

}
}