preg_match deprication, null point prevention

[erth5]

Warning: preg_match(): Passing null to parameter #2 ($subject) of type string is deprecated

Resolution: vendor\stepanenko3\nova-cards\src\Http\Controllers\ScheduledJobsController.php

     20 $nextDueDate = $this->getNextDueDateForEvent($event, $timezone);
     21
  +  22 $command = $event->command ?? '';
     23
+-   24 preg_match("/artisan.*?\s(.*)/", $command, $matches);