Date range display value

dateRange.php

<?php

    /**
     * Determine the best way to render the date based on conditions
     *
     * @return string | null
     */
    public function getEventDate()
    {
        $start = DBDate::create()->setValue($this->owner->StartDate);
        $end = DBDate::create()->setValue($this->owner->EndDate);

        // Nothing to display if no start date
        if (!$start) {
            return null;
        }

        // If no end date OR hide end date, just display start date
        if (!$end) {
            return $start->Format('d MMM y');
        }

        $d1 = $start->Format('d');
        $d2 = $end->Format('d');
        $m1 = $start->Format('MMM');
        $m2 = $end->Format('MMM');
        $y1 = $start->Format('y');
        $y2 = $end->Format('y');
        $str = '';

        if (!$d1 || !$m2 || !$y2) {
            return "$d1 $m1 $y1";
        } elseif ($y1 != $y2) {
            return "$d1 $m1 $y1 – $d2 $m2 $y2";
        } elseif ($m1 != $m2) {
            $str = "$d1 $m1 – $d2 $m2 $y2";
        } elseif ($d1 != $d2) {
            $str = "$d1 – $d2 $m1 $y2";
        } else {
            $str = "$d1 $m1 $y2";
        }

        return $str;
    }
}