Automattic / jetpack

		$orderby = isset( self::wp_query()->query_vars['orderby'] ) ?

			self::wp_query()->query_vars['orderby'] : '';

		$post_date = ( ! empty( $post->post_date ) ? $post->post_date : false );

		switch ( $orderby ) {

			case 'modified':

				return $post->post_modified;

			case 'date':

			case '':

				return $post_date;

			default:

				return false;

		}

	}

	/**

		$orderby = isset( $query->query_vars['orderby'] ) ? $query->query_vars['orderby'] : '';

		switch ( $orderby ) {

			case 'modified':

				return 'post_modified';

			case 'date':

			case '':

				return 'post_date';

			default:

				return false;

		}

	}

	/**