class CompoundObserver

CompoundObserver is a Bindable object which knows how to listen to multiple values (registered via addPath or addObserver) and invoke a callback when one or more of the values have changed.

var obj = new ObservableMap.from({'a': 1, 'b': 2}); var otherObj = new ObservableMap.from({'c': 3});

var observer = new CompoundObserver()

 ..addPath(obj, 'a');
 ..addObserver(new PathObserver(obj, 'b'));
 ..addPath(otherObj, 'c');
 ..open((values) {
   for (int i = 0; i < values.length; i++) {
     print('The value at index $i is now ${values[i]}');
   }
 });

obj'a' = 10; // print will be triggered async