src/Markdown.php
protected function grabReferences($lineNumber)
    {
        $content = $this->dataObject->getLine($lineNumber);

        // grab urls with title
        $content = preg_replace_callback('/\[(.*)\]:\s?(.*)\s?"(.*)"/U', function ($found) {
            $key = trim($found[1]);
            $url = trim($found[2]);
            $title = trim($found[3]);

            $this->dataObject->addReference($key, [
                'url' => $url,
                'title' => $title,
                'type' => 'url',
            ]);

            return '';
        }, $content);

        // grab urls without title
        $content = preg_replace_callback('/\[(.*)\]:\s?(.*)/', function ($found) {
            $key = trim($found[1]);
            $url = trim($found[2]);

            $this->dataObject->addReference($key, [
                'url' => $url,
                'title' => '',
                'type' => 'url',
            ]);

            return '';
        }, $content);

        return $content;
    }
protected function grabReferences($lineNumber)
    {
        $content = $this->dataObject->getLine($lineNumber);

        // grab urls with title
        $content = preg_replace_callback('/\[(.*)\]:\s?(.*)\s?"(.*)"/U', function ($found) {
            $key = trim($found[1]);
            $url = trim($found[2]);
            $title = trim($found[3]);

            $this->dataObject->addReference($key, [
                'url' => $url,
                'title' => $title,
                'type' => 'url',
            ]);

            return '';
        }, $content);

        // grab urls without title
        $content = preg_replace_callback('/\[(.*)\]:\s?(.*)/', function ($found) {
            $key = trim($found[1]);
            $url = trim($found[2]);

            $this->dataObject->addReference($key, [
                'url' => $url,
                'title' => '',
                'type' => 'url',
            ]);

            return '';
        }, $content);

        return $content;
    }
@param int $lineNumber

@return null|BlockInterface|mixed|string