Some new features in PHP 8.4:

1. Property Hooks

Property hooks allow custom logic for property access directly within the property definition.

php
class User {
    public string $name {
        get => $this->name;
        set => $this->name = strtoupper($value);
    }
}

$user = new User();
$user->name = 'john'; // Automatically converts to uppercase
echo $user->name; // Output: JOHN

2. Asymmetric Visibility

Asymmetric visibility lets you define different visibility for reading and writing properties.

php
class BankAccount {
    public float $balance {
        public get;
        private set;
    }

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

$account = new BankAccount();
$account->deposit(100.00);
echo $account->balance; // Output: 100.00
// $account->balance = 50.00; // Error: Cannot write to private property

3. Class Instantiation Without Parentheses

If a class doesn’t require constructor arguments, parentheses are now optional.

php
class MyClass {}

$object = new MyClass; // No parentheses needed
var_dump($object instanceof MyClass); // Output: bool(true)

4. New Array Functions

These functions simplify common array operations.

php
$data = [1, 2, 3, 4, 5];

// Find the first value greater than 3
$result = array_find($data, fn($x) => $x > 3);
echo $result; // Output: 4

// Check if any value is greater than 4
$result = array_any($data, fn($x) => $x > 4);
var_dump($result); // Output: bool(true)

// Check if all values are greater than 0
$result = array_all($data, fn($x) => $x > 0);
var_dump($result); // Output: bool(true)

5. New Multibyte String Functions

Work with multibyte strings more effectively.

php
$text = "ápple";

// Capitalize the first character
echo mb_ucfirst($text); // Output: Ápple

// Lowercase the first character
echo mb_lcfirst("APPLE"); // Output: aPPLE

// Trim multibyte characters
echo mb_trim("   ápple   "); // Output: ápple

6. Deprecated Attribute

Mark code elements as deprecated.

php
class MyLibrary {
    #[Deprecated("Use newMethod() instead.")]
    public function oldMethod() {
        echo "This method is deprecated.";
    }

    public function newMethod() {
        echo "This is the new method.";
    }
}

7. HTML5 Support with DomHTMLDocument

Enhanced HTML parsing with the new DomHTMLDocument class.

php
$html = <<


Hello World

HTML;

$doc = new DomHTMLDocument();
$doc->loadHTML($html);
echo $doc->getElementsByTagName('p')->item(0)->textContent; // Output: Hello World