Create URL slugs from UTF-8 titles

<?php

declare(strict_types=1);

/** Turn a UTF-8 title into a lowercase ASCII slug suitable for URLs. */
function slugify(string $title, int $maxLength = 60): string
{
    if (function_exists('iconv')) {
        $ascii = @iconv('UTF-8', 'ASCII//TRANSLIT//IGNORE', $title);
        if ($ascii !== false) {
            // Some iconv builds mark accents with ASCII symbols; drop those marks.
            $title = preg_replace('/[\x60\'"^~]+/', '', $ascii) ?? $ascii;
        }
    }
    $slug = preg_replace('/[^a-z0-9]+/', '-', strtolower($title)) ?? '';
    $slug = trim($slug, '-');
    if ($slug === '') {
        return 'untitled';
    }
    $slug = substr($slug, 0, $maxLength);
    return rtrim($slug, '-');
}

$titles = ['Hello, World!', 'Crème brûlée & café', '  -- Already A Slug --  ', '???'];
foreach ($titles as $title) {
    echo slugify($title), PHP_EOL;
}