PHP: Convert a string to snake case

str2snake.php

    /**
     * Convert a string to snake case.
     *
     * @param string $value
     * @param string $delimiter Default to underscore
     *
     * @return string
     */
    public function snake(string $value, ?string $delimiter = null): string
    {
        if (!\ctype_lower($value)) {
            $value = (string) \preg_replace('/\s+/u', '', \ucwords($value));
            $value = (string) \mb_strtolower(\preg_replace(
                '/(.)(?=[A-Z])/u',
                '$1' . ($delimiter ?? '_'),
                $value
            ));
        }

        return $value;
    }

From eoneopay/utils/src/Str.php