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';
}
I don't see the need to do so much dynamic work.  I would establish a lookup array to access.  This will be clean, direct, and easy to maintain.  If the incoming format is not found, just fallback to m-d-Y using the null coalescing operator.
private $formatLookup = [
    'YYYY-MM-DD' =&gt; 'Y-m-d',
    'YYYY/MM/DD' =&gt; 'Y/m/d',
];

public function dateFormatStringConvert(string $format) : string
{
    return $this-&gt;formatLookup[$format] ?? 'm-d-Y';
}

With this setup, you never need to touch the processing method, you only need to maintain the lookup array.