Matching property must exist when on...Changed listeners are used

[cpetrov]

Since tabris-decorators@3.7.0, using listeners named on<property name>Changed requires <property name> to be a property declared in the class. The naming pattern on...Changed could be used for e.g. business logic unrelated to changes of class properties, thus the current behavior is overly restrictive. Moreover, this is an unexpected breaking change in tabris-decorators@3.7.0 over the previous version tabris-decorators@3.6.1, as usage of listeners named on...Changed without a matching property was tolerated in tabris-decorators@3.6.1. This breaking change introduces hard to find bugs for users who updated to tabris-decorators@~3.7.0 and use listeners named on...Changed without a matching property.

Example:

import { event } from 'tabris-decorators';

class Foo {
  @event onBarChanged;
}

new Foo().onBarChanged(() => console.log('bar changed'));

>  Could not load main module: Error: Target has no property "bar"