public function toCamelCase(string $var, bool $strict = true): string
    {
        $var = mb_strtolower($this->c::forceAscii($var));
        $var = preg_replace('/[^a-z0-9]+/u', '_', $var);
        $var = $this->c::mbTrim($var, '', '_');

        if ($strict && $var && !preg_match('/^[a-z]/u', $var)) {
            $var = 'x'.$var; // Force `^[a-z]`.
        }
        return $camelCase = $var ? preg_replace_callback('/_(.)/u', function (array $m): string {
            return mb_strtoupper($m[1]); // e.g., `_x` becomes `X` for camelCase.
        }, $var) : $var; // Converts variable into camelCase variable.
    }