Illuminate\Support\Collection::search PHP Method

    public function search($value, $strict = false)
    {
        if (!$this->useAsCallable($value)) {
            return array_search($value, $this->items, $strict);
        }
        foreach ($this->items as $key => $item) {
            if (call_user_func($value, $item, $key)) {
                return $key;
            }
        }
        return false;
    }

 /**
  * Crawl and process a single URL.
  * @param $url string
  * @return mixed|null
  */
 protected function crawlUrl($url, $parentUrl = null)
 {
     if (!$url || $this->crawled->search($url) !== false || Str::startsWith($url, "#")) {
         return null;
     }
     $this->log("Crawling URL: " . $url);
     $ch = curl_init();
     curl_setopt($ch, CURLOPT_URL, $url);
     curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
     curl_setopt($ch, CURLOPT_USERAGENT, $this->agent);
     curl_setopt($ch, CURLOPT_HEADER, 1);
     $response = curl_exec($ch);
     $headerSize = curl_getinfo($ch, CURLINFO_HEADER_SIZE);
     $header = $this->parseHeader(substr($response, 0, $headerSize));
     $body = substr($response, $headerSize);
     curl_close($ch);
     $this->crawled->push($url);
     if (!$this->validate($header, $body, $url, $parentUrl)) {
         return null;
     }
     $processed = $this->processHtml($url, HtmlDomParser::str_get_html($body));
     $this->add($processed);
     // Recursively crawl other URLs that were found.
     foreach ($processed['urls'] as $href) {
         $this->crawlUrl($href, $url);
     }
 }