Dart by Example: Null-Aware Operators

main() {
  // The ?? operator returns the first expression IFF it is not null
  var monday = 'doctor';
  var tuesday;
  var next = tuesday ?? monday;
  print('next appointment: $next');
  // the ??= operator assigns a value IFF it is not null
  var wednesday;
  next ??= wednesday;
  print('next appointment: $next');
  // the ? operator calls a function IFF the object is not null
  String thursday;
  var length = thursday?.length;
  print('length: $length');
}
 

$ dart nullaware.dart
next appoinment: doctor
next appointment: doctor
length: null

by @jryanio | source | license