datetime – JavaScript date format string to php date format string convert

Please find the following scenario, I’ve dynamic JS date format string from API but I am looking for the best way to convert the format that accepts in PHP date format. For now, I wrote it my own way but I doubt there should be a standard solution.

JS time format: YYYY-MM-DD / YYYY/MM/DD
Need PHP format: Y-m-d / Y/m/d

I’ve written the solution this way, please let me know if you find something else in a better way than this.

function dateFormatStringConvert(string $format) : string
{
    foreach (('-', '/') as $operator) {
        if (strpos($format, $operator) !== false) {
            return implode($operator, array_map(function ($piece){
                return $piece(0)=='M' || $piece(0)=='D' ? strtolower($piece(0)) : $piece(0);
            }, explode($operator, $format)));
        }
    }
    return 'm-d-Y';
}