public function clear( $what = [] ) {

		$defaults = [
			'criteria'  => [],
			'offset'    => 0,
			'limit'     => 0,
			'orderby'   => [],
		];

		$what = (array) $what;

		if( empty($what) )
			$what = array_keys($defaults);

		foreach( $what as $k ) {
			$this->$k = $defaults[$k];
		}

		return $this;

	}