Polymer. Way to dynamically add or remove observer - polymer

Question

Is there a way to add or remove observer not in the moment of element initing?
I can define observer this way:
observers: ['dataChanged(data.*)']
Can i remove this observer later or can I set this observer different way than that?

Answer 1

You can easily add an observer dynamically, either by:
this._addObserverEffect("property", observerFunction);
or
this._addComplexObserverEffect("dataChanged(data.*)");
Removing is harder and Polymer does not provide a function to do this. Although you could search for it in the _propertyEffects array, I wouldn't recommend it. Maybe just check in your observer function whether it should still be active, and return if not.

Answer 2

you maybe can try this way:
configure your data property in the element with notify: true, so you can add a listener to changes with plain js
var element=document.querySelector("#YOUR-ELE-ID");
element.addEventListener("data-changed", function(e) {
//triggered when data property changes
});
https://www.polymer-project.org/1.0/docs/devguide/properties#notify
and to remove the bound listener you can call removeEventListener
https://developer.mozilla.org/de/docs/Web/API/EventTarget/removeEventListener
Example 1 - plain JS :
document.addEventListener('WebComponentsReady', function(e) {
var element=document.querySelector("#YOUR-ELE-ID");
element.addEventListener("data-changed", function(e) {
//triggered when data property changes
});
});
Example 2 - in custom element:
//...element definition...
ready: function() {
var element=document.querySelector("#YOUR-ELE-ID");
element.addEventListener("data-changed", function(e) {
//triggered when data property changes
});
}