Stempel Waktu Unix dan date()

<?php
$now = time();
echo $now;           // e.g. 1716800000
echo gettype($now);  // integer

// 1 day in seconds
$tomorrow = time() + 86400;
$yesterday = time() - 86400;

echo date('Y-m-d', $tomorrow);  // tomorrow's date

<?php
$ts = time();

echo date('Y-m-d', $ts);           // 2024-05-27
echo date('d/m/Y', $ts);           // 27/05/2024
echo date('D, d M Y H:i:s', $ts);  // Mon, 27 May 2024 14:30:00
echo date('c', $ts);               // ISO 8601: 2024-05-27T14:30:00+00:00
echo date('U', $ts);               // Unix timestamp (same as time())

<?php
// mktime(hour, min, sec, month, day, year)
$ts = mktime(0, 0, 0, 12, 25, 2024);  // Christmas 2024 midnight
echo date('Y-m-d', $ts);  // 2024-12-25

// Last day of month trick:
$lastDay = mktime(0, 0, 0, 3, 0, 2024);  // day 0 = last day of Feb
echo date('Y-m-d', $lastDay);  // 2024-02-29 (leap year)

<?php
echo strtotime('2024-12-25');       // timestamp
echo strtotime('next Monday');      // next Monday's timestamp
echo strtotime('+1 week');          // 7 days from now
echo strtotime('last day of this month');  // end of month
echo strtotime('2024-01-01 +3 months');   // April 1, 2024

<?php
$subscriptionStart = strtotime('2024-01-15');
$oneYearLater = strtotime('+1 year', $subscriptionStart);
$trialEnd = strtotime('+14 days');

echo date('Y-m-d', $oneYearLater);  // 2025-01-15
echo date('Y-m-d', $trialEnd);      // 14 days from today

// Days until event:
$event = strtotime('2024-12-31');
$daysLeft = (int) (($event - time()) / 86400);
echo "Days until NYE: $daysLeft";

<?php
// Store as ISO string (recommended for readability):
$created_at = date('Y-m-d H:i:s');  // '2024-05-27 14:30:00'

// Store as Unix timestamp (fast integer comparison):
$created_ts = time();  // 1716800000

// Convert back:
$ts = strtotime($created_at);
$fmt = date('Y-m-d H:i:s', $created_ts);

<?php
$dt = date_create('2024-05-27');
echo date_format($dt, 'D, d M Y');  // Mon, 27 May 2024

date_modify($dt, '+30 days');
echo date_format($dt, 'Y-m-d');  // 2024-06-26

// Equivalent OO:
$dt2 = new DateTime('2024-05-27');
$dt2->modify('+30 days');
echo $dt2->format('Y-m-d');

<?php
var_dump(checkdate(2, 29, 2024));  // true (leap year)
var_dump(checkdate(2, 29, 2023));  // false (not leap year)
var_dump(checkdate(13, 1, 2024));  // false (no month 13)
var_dump(checkdate(1, 31, 2024));  // true

<?php
$start = microtime(true);

// Simulate work
for ($i = 0; $i < 100000; $i++) {}

$end = microtime(true);
$duration = ($end - $start) * 1000;  // milliseconds
echo sprintf('Took %.2f ms', $duration);