Online PHP editor | refs for hmcm6

<?php function DateSameMonth($date_iso, $add_sub_months = 1, $operator = "+") { $mdate = [0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]; $date = new DateTime($date_iso); $d = (int)$date->format('d'); $m = (int)$date->format('m'); $y = (int)$date->format('Y'); if ($m == 2) { $mdate[$m] = (($y % 4) === 0) ? (($d <= 29) ? $d : 29) : (($d <= 28) ? $d : 28); } if($d == 1) { $mod = "first day of "; } elseif($d == $mdate[$m]) { $mod = "last day of "; } else { $mod = ""; } $date->modify($mod . $operator . $add_sub_months . ' months'); return $date->format("Y-m-d"); } var_dump(DateSameMonth("2022-01-31", 3, "-")); var_dump(DateSameMonth("2022-11-30", 3, "+")); var_dump(DateSameMonth("2022-01-31", 25, "+")); //leap year var_dump(DateSameMonth("2022-01-16", 25, "+")); echo "\n\nTEST: FIRST OF (+1 month)\n"; for($i=1; $i<=12; $i++){ $start = "2023-". $i ."-01"; echo $start . " ----> ". DateSameMonth($start, 1, "+") . "\n"; } echo "\n\nTEST: LAST OF (+12 months)\n"; for($i=1; $i<=12; $i++){ $start = date("Y-m-t", strtotime("2023-". $i ."-01")); echo $start . " ----> ". DateSameMonth($start, 12, "+") . "\n"; } echo "\n\nTEST: RANDOM DAY (+1 month)\n"; for($i=1; $i<=50; $i++){ $start = date("Y-m-") . rand(1, 27); echo $start . " ----> ". DateSameMonth($start, 1, "+") . "\n"; } echo "\n\nTEST: RANDOM DAY (-1 month)\n"; for($i=1; $i<=50; $i++){ $start = date("Y-m-") . rand(1, 27); echo $start . " ----> ". DateSameMonth($start, 1, "-") . "\n"; }