protected static function array_map_assoc( callable $callback, array $array ) {
		$new = [];

		foreach ( $array as $k => $v ) {
			$u = $callback( $k, $v );

			if ( ! empty( $u ) ) {
				$new[ \key( $u ) ] = \current( $u );
			}
		}

		return $new;
	}