whenOrNull<TResult extends Object?> method

  1. @optionalTypeArgs
TResult? whenOrNull<TResult extends Object?>({
  1. TResult? done()?,
  2. TResult? error(
    1. String error
    )?,
  3. TResult? progress()?,
})

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()?  done,TResult? Function( String error)?  error,TResult? Function()?  progress,}) {final _that = this;
switch (_that) {
case PickerLoadStatusDone() when done != null:
return done();case PickerLoadStatusError() when error != null:
return error(_that.error);case PickerLoadStatusProgress() when progress != null:
return progress();case _:
  return null;

}
}