disconnectedCallback method
Implementation
@override
void disconnectedCallback() {
  super.disconnectedCallback();
  _updateIDMap(null, oldID: _id);
  _updateNameMap(null, oldName: getAttribute(_NAME));
}@override
void disconnectedCallback() {
  super.disconnectedCallback();
  _updateIDMap(null, oldID: _id);
  _updateNameMap(null, oldName: getAttribute(_NAME));
}