WordPress 上带有前缀的自定义目录

Question

我正在使用此 PHP 在 WordPress 上生成目录：

add_filter('the_content', function ($content) {
    global $tableOfContents;
    $tableOfContents = "
    <div class='widget widget_toc'>
        <h2 class='widgettitle'>Table of Contents <span class='toggle'></span></h2>
        <ul>
        <li><a href='#preface'>Preface</a></li>
        ";
    
    $index = 1;
    $indexes = [2 => 0, 3 => 0, 4 => 0, 5 => 0, 6 => 0];
    
    // Insert the IDs and create the TOC.
    $content = preg_replace_callback('#<(h[1-3])(.*?)>(.*?)</\1>#si', function ($matches) use (&$index, &$tableOfContents, &$indexes) { // H3 Max
        $tag = $matches[1];
        $title = strip_tags($matches[3]);
        $hasId = preg_match('/id=(["\'])(.*?)\1[\s>]/si', $matches[2], $matchedIds);
        $id = $hasId ? $matchedIds[2] : $index++ . '-' . sanitize_title($title);
        
        // Generate the prefix based on the heading value.
        $prefix = '';
        
        foreach (range(2, $tag[1]) as $i) {
            if ($i == $tag[1]) {
                $indexes[$i] += 1;
            }
            $prefix .= $indexes[$i] . '.';
        }
        
        $title = "<span class='prefix'>$prefix</span> $title";
        $tableOfContents .= "<li class='item-$tag'><a href='#$id'>$title</a></li>";
        if ($hasId) {
            return $matches[0];
        }
        return sprintf('<%s%s id="%s">%s</%s>', $tag, $matches[2], $id, $matches[3], $tag);
    }, $content);
    $tableOfContents .= '</ul></div>';
    return $content;
});

function get_the_table_of_contents() {
    global $tableOfContents;
    return $tableOfContents;
}

function toc_shortcode(){
    echo get_the_table_of_contents();
}
add_shortcode('toc', 'toc_shortcode');

我得到的是 4.3 和 4.4 而不是 4.1 和 4.2，因为它们已经在标题 2 中增加了。

如何修改此代码以纠正此问题？