PHP 8 New Feature: Constructor Property Promotion Made Simple

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Constructor Property Promotion is a new syntax in PHP 8 that allows class property declaration and constructor assignment right from the constructor.

In PHP (before version 8), when we created a class, we had to:

  1. Declare properties separately.
  2. Assign them inside the constructor.

This meant writing a lot of repeated code.

Old Way (Before PHP 8)

<?php
class Student {
    public string $name;
    public int $age;

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

$student = new Student("Amit", 21);
echo $student->name; // Output: Amit

?>

Here we are writing $name and $age two times:

  • Once for property declaration
  • Once again in constructor assignment

New Way in PHP 8 (Constructor Property Promotion)

In PHP 8, we can directly declare and assign class properties inside the constructor parameters.

<?php
class Student {
    public function __construct(
        public string $name,
        public int $age
    ) {}
}

$student = new Student("Amit", 21);
echo $student->name; // Output: Amit
?>

Benefits:

  • Less code, more readability
  • Properties are automatically created and assigned
  • No need to repeat yourself

Real-Life Example

<?php
class BankAccount {
    public function __construct(
        public string $holderName,
        public string $accountNumber,
        public float $balance
    ) {}
}

$account = new BankAccount("Rahul Sharma", "1234567890", 15000.50);

echo $account->holderName;   // Rahul Sharma  
echo $account->accountNumber; // 1234567890  
echo $account->balance;       // 15000.5  

?>

Here, all details (holderName, accountNumber, balance) are automatically created and assigned in one step.

Constructor Property Promotion in PHP 8 reduces boilerplate code and makes classes shorter and cleaner.