whenOrNull<TResult extends Object?> method
TResult?
whenOrNull<TResult extends Object?>({})
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(File file)? file,
TResult? Function(String url)? network,
}) {
final _that = this;
switch (_that) {
case XXFile() when file != null:
return file(_that.file);
case XXImage() when network != null:
return network(_that.url);
case _:
return null;
}
}