docs: function del (obj, key) {
  	  var ob = obj.__ob__;
  	  if (obj._isVue || (ob && ob.vmCount)) {
  	    "development" !== 'production' && warn(
  	      'Avoid deleting properties on a Vue instance or its root $data ' +
  	      '- just set it to null.'
  	    );
  	    return
  	  }
  	  if (!hasOwn(obj, key)) {
  	    return
  	  }
  	  delete obj[key];
  	  if (!ob) {
  	    return
  	  }
  	  ob.dep.notify();
  	}