Whats new in PHP 8.4

PHP 8.4 has arrived with exciting new features that make coding easier and boost performance. This article breaks down the key updates with clear examples, helping developers of all skill levels understand and apply them effortlessly.

Currently Supported Versions

source PHP Supported Versions

1. New Array Functions

PHP 8.4 adds new array functions that save you from writing manual loops.

Example:

$arrayNumbers = [1, 2, 3, 4, 5];

/**
 * Find the first even number
 */
$firstEven = array_find($arrayNumbers, fn($n) => $n % 2 === 0);
echo $firstEven; // Output: 2

/**
 * Check if any number is greater than 2
 */
$hasBigNumber = array_any($arrayNumbers, fn($n) => $n > 2);
var_dump($hasBigNumber); // Output: bool(true)

/**
* Check if all numbers are positive
*/
$allPositive = array_all($arrayNumbers, fn($n) => $n > 0);
var_dump($allPositive); // Output: bool(true)

2. Simplified Object Instantiation

You can now create an object and call a method on it immediately, without wrapping the instantiation in parentheses.

Example:

class Logger {
    /**
     * Logging info message
     * @param $message string
     */
    public function info(string $message): void {
        echo $message;
    }

    /**
     * Logging error message
     * @param $message string
     */
    public function error(string $message): void {
        echo $message;
    }
}

/**
 * Create an object and call a method in one step
 */
new Logger()->info('Logging info message'); // Output: Logging info message

3. Property Hooks

Property hooks let you customise what happens when you get or set a property. This removes the need for separate getter and setter methods.

Example:

class User {
    private string $name;
    private int $lastName;

    public function __construct(string $name, string $lastName) {
        $this->name = $name;
        $this->lastName = $lastName;
    }

    /**
     * This property combines first and last name
     */
    public string $fullName {
        get => $this->name . ' ' . $this->lastName;
        set => [$this->name, $this->lastName] = explode(' ', $value, 2);
    }
}

$user = new User('John', 'Doe');
echo $user->fullName; // Output: John Doe

$user->fullName = 'Jane Smith'; // Updates first and last names
echo $user->fullName; // Output: Jane Smith

4. Asymmetric Visibility

You can now set different levels of visibility for reading and writing a property. For example, a property can be readable by everyone but only writable by the class itself.

Example:

class Wallet {
    /**
     * Public read, private write
     */
    public private(set) float $balance;

    public function __construct(float $initialBalance) {
        $this->balance = $initialBalance;
    }

    public function deposit(float $amount): void {
        $this->balance += $amount;
    }
}

$wallet = new Wallet(100.0);
echo $wallet->balance; // Output: 100

$wallet->deposit(50.0); // Adds 50 to the balance
echo $wallet->balance; // Output: 150

/**
 * The following line will cause an error:
 */
$wallet->balance = 200.0;

5. Deprecation of Implicit Nullable Types

PHP 8.4 requires you to explicitly declare when a parameter can be null. This makes code easier to understand and maintain.

Example:

/**
* PHP 8.4 (Recommended):
*/
function process(?string $data = null) {
    echo $data ?? 'No data provided';
}

6.Lazy Objects

Lazy objects let you delay creating an object until it's actually used, which can save resources.

Example:

class ExpensiveResource {
    public function __construct() {
        // Simulate a time-consuming setup
        sleep(2);
    }

    public function doWork(): void {
        echo 'Working...';
    }
}

/**
 * Use a lazy object to delay creation
 */
$initializer = fn() => new ExpensiveResource();
$reflector = new ReflectionClass(ExpensiveResource::class);
$resource = $reflector->newLazyProxy($initializer);

/**
 * The object isn't created yet
 */
$resource->doWork(); // Now the object is created and "Working..." is printed