FluentDOM\Xpath::firstOf PHP Method

    public function firstOf($expression, \DOMNode $contextNode = NULL, $registerNodeNS = NULL)
    {
        $nodes = $this->evaluate($expression, $contextNode, $registerNodeNS);
        if ($nodes instanceof \DOMNodeList && $nodes->length > 0) {
            return $nodes->item(0);
        }
        return NULL;
    }