Null Safety

Null-Aware

?? and ?.

?? returns a fallback when the left side is null. ?. only calls the method if the receiver is non-null.

Program

Play the program to fall back to a default and safely read a length.

null_aware.dart 
void main() {
  String? name;
  var display = name ?? 'default';
  print(display);
  name = 'Ada';
  print(name?.length);
}
?? `a ?? b` is `a` when not null, otherwise `b`.
?. `x?.method()` returns `null` when `x` is null instead of throwing.
safe access Both operators avoid null dereferences without a manual `if`.