be-propagating creates a subscribable EventTarget, which watches for changes to a provided list of properties of the element it adorns, and the event target emits events with the same name every time the property value changes.
In the examples below, we assume some-element is a custom element that has property setters myProp1, myProp2
<some-element be-propagating='
"propagate": ["myProp1", "myProp2"]
'></some-element>The EventTarget object can be obtained from someElement.beEnhanced.bePropagating.propagator.