PHP get month interval.

gistfile1.txt

  public static function getMonthInterval($date) {
    $month_interval = [];

    // Get start month date.
    $date_obj = new \DateTime($date);
    $date_obj->modify('first day of this month');
    $month_interval['start'] = $date_obj->getTimestamp();

    // Get end month date.
    $date_obj->modify('last day of this month');
    $date_obj->setTime(23, 59, 59);
    $month_interval['end'] = $date_obj->getTimestamp();

    return $month_interval;
  }