Polymer.dart bindings without custom element. In this example, we will only bind using binding delegates.

CountNotifier.dart

class CountNotifier extends ChangeNotifier {
  int _count = 0;
  int get count => _count;
  set count(int count) {
    _count = notifyPropertyChange(#count, _count, count);
  }
}

main.dart

CountNotifier counter = new CountNotifier();
Map globals = {
  "count": counter,
};

templateBind(querySelector('#counter'))
    ..bindingDelegate = new PolymerExpressions(globals: globals);

querySelector("#inc_count").onClick.listen((_) {
  counter.count++;
});

template.html

<template id="counter" bind>
  You have clicked {{count.count}} times.
</template>
<input type="button" id="inc_count" value="Count">