strtotime is not converting date correctly

Question

Below is the code which I am using to identify continuous range of dates stored in an array

$lastDate = null;
$currentRange = array();
$holidays=array("2022-12-15","2022-12-16","2022-12-17","2022-12-28","2022-12-29");
    
    
    foreach($holidays as $holiday)
    {
        
        $time_stamp=strtotime($holiday);
        
       
        if($time_stamp<=$fromdate)
        {
             
             if (null === $lastDate)
                 {
                    $currentRange[] = $time_stamp;
                    
                 }
            else
                 {

                    // get the DateInterval object
                    $interval = ($time_stamp-$lastDate)/86400;
                        
                    // // DateInterval has properties for 
                    // // days, weeks. months etc. You should 
                    // // implement some more robust conditions here to 
                    // // make sure all you're not getting false matches
                    // // for diffs like a month and a day, a year and 
                    // // a day and so on...

                     if ($interval == 1) {
                        // add this date to the current range
                        $currentRange[] = date('m-d-Y',$time_stamp);   
                        
                        } else {
                        // store the old range and start anew
                        //$ranges[] = $currentRange;
                        $currentRange = array(date('m-d-Y',$time_stamp));
                        
                    }
                  }
                  $lastDate = $time_stamp;
        }

When I am displaying $currentrange Output is:  [1671042600, '12-16-2022', '12-17-2022']

The first timestamp is not getting converted to date time format.

Also the first timestamp returned "1671042600" corresponds to '12-14-2022' while it should be '12-15-2022'.

I am not able to figure out why this weird response, only the first timestamp is not getting correctly converted to date while other timestamps are correctly getting converted to date

Answer 1

Change

$time_stamp=strtotime($holiday);

To

$time_stamp = (strtotime($holiday)?strtotime($holiday):$holiday);