Recursively generating heading numbers

For a project I needed to create a page that would show organizational information. Each item is either a root item or a child item. The child items can have child items themselves. This is a recursive structure, which meant I could easily generate header numbers and depth.

/**
 * The heading number including super-items. E.g.: "1.1".
 *
 * @return Attribute<string, void>
 */
protected function headingNumber(): Attribute
{
    return Attribute::get(fn(): string => !$this->parent
        ? "$this->sort_index"
        : "{$this->parent->heading_number}.{$this->sort_index}"
    );
}

/**
 * How many levels this item is, starting at 1.
 *
 * @return Attribute<int, void>
 */
protected function depth(): Attribute
{
    return Attribute::get(fn(): int => 1 + ($this->parent?->depth ?? 0));
}

This makes use of Laravel’s attribute accessors to create computed properties, which can then be accessed like any other property.

Reflection

A WYSIWYG¹ editor like is another option. The downside of that is that if you want to make any change to the structure of the page, you are going to have to manually re-number all the headings, as I don’t know of any WYSIWYG editor libraries that support auto numbering of headings. On top of that, it seems like overkill to use a WYSIWYG editor for this.