Numeric Input polymer component

numeric_input.dart

import 'package:polymer/polymer.dart';

@CustomTag('numeric-input')
class NumericInput extends PolymerElement {

  num _value;

  @published
  num get value => _value;

  set value(num newValue) {
    if (_value != newValue) {
      if (newValue is String) {
        try {
          newValue = num.parse(newValue as String);
        } catch (e) {
          return;
        }
      }
      _value = notifyPropertyChange(#value, _value, newValue);
    }
  }

  NumericInput.created() : super.created() {

  }

  @override
  void attached() {
    super.attached();
  }
}

numeric_input.html

<link rel="import" href="../../../../packages/polymer/polymer.html">

<polymer-element name="numeric-input">
    <template>
        <input flex type="number" value="{{value}}">
    </template>

    <script type="application/dart" src="numeric_input.dart"></script>
</polymer-element>