Implement this class to build a WebComponent.
lifecycle-callback that is called, when an instance is adopted by another DOM
this callback is used, when building the component in native-js (since ES2015-classes are not supported by Kotlin/JS by now)
convenience method to get a Flow of the changes of a specific observed attributes.
lifecycle-callback that is called, when an instance of the component is added to the DOM
lifecycle-callback that is called, when an instance of the component is removed from the DOM
this method builds the content of the WebComponent that will be added to it's shadow-DOM.
call this method in init to link an external stylesheet.
call this method in add style information from a static String.
a Flow of all changes made to observed attributes.