in-viewport-10.js

_unbindListeners() {
  const elementId      = get(this, 'elementId');
  const viewportUseRAF = get(this, 'viewportUseRAF');

  Ember.warn('No elementId was found on this Object, `viewportSpy` will' +
    'not work as expected', elementId);

  if (viewportUseRAF) {
    next(this, () => {
      window.cancelAnimationFrame(rAFIDS[elementId]);
      rAFIDS[elementId] = null;
    });
  }

  forEach(listeners, (listener) => {
    const { context, event } = listener;
    $(context).off(`${event}#${elementId}`);
  });
}