Chronos focuses on providing immutable date/datetime objects. Immutable objects help ensure that datetime objects aren't accidentally modified, keeping data more predictable.

Installing with composer:

$ composer require cakephp/chronos 

For details on the (minimum/maximum) PHP version see version map.

<?php require 'vendor/autoload.php'; use Cake\Chronos\Chronos; printf("Now: %s", Chronos::now());

Chronos was originally compatible with Carbon but has diverged and no longer extends the PHP DateTime and DateTimeImmutable classes.

Immutable objects have a number of advantages:

1. Using immutable objects is always free of side-effects.
2. Dates and times don't accidentally change underneath other parts of your code.

With those benefits in mind, there are a few things you need to keep in mind when modifying immutable objects:

// This will lose modifications $date = new Chronos('2015-10-21 16:29:00'); $date->modify('+2 hours'); // This will keep modifications $date = new Chronos('2015-10-21 16:29:00'); $date = $date->modify('+2 hours');

PHP only offers datetime objects as part of the native extensions. Chronos adds a number of conveniences to the traditional DateTime object and introduces a ChronosDate object. ChronosDate instances their time frozen to 00:00:00 and the timezone set to the server default timezone. This makes them ideal when working with calendar dates as the time components will always match.

use Cake\Chronos\ChronosDate; $today = new ChronosDate(); echo $today; // Outputs '2015-10-21' echo $today->modify('+3 hours'); // Outputs '2015-10-21'

Like instances of Chronos, ChronosDate objects are also immutable.

When you need to work with just times (without dates), use ChronosTime:

use Cake\Chronos\ChronosTime; $time = new ChronosTime('14:30:00'); echo $time->format('g:i A'); // 2:30 PM // Create from components $time = ChronosTime::create(14, 30, 0); // Arithmetic $later = $time->addHours(2)->addMinutes(15);

ChronosTime is useful for recurring schedules, business hours, or any scenario where the date is irrelevant.

Chronos provides setTestNow() to freeze time during testing:

use Cake\Chronos\Chronos; // Freeze time for predictable tests Chronos::setTestNow('2024-01-15 10:00:00'); $now = Chronos::now(); // Always 2024-01-15 10:00:00 // Reset to real time Chronos::setTestNow(null);

For dependency injection, use ClockFactory which implements PSR-20:

use Cake\Chronos\ClockFactory; $clock = new ClockFactory('UTC'); $now = $clock->now(); // Returns Chronos instance // In your service class OrderService { public function __construct(private ClockInterface $clock) {} public function createOrder(): Order { return new Order(createdAt: $this->clock->now()); } }

A more descriptive documentation can be found at book.cakephp.org/chronos/3/.

API documentation can be found on api.cakephp.org/chronos.