Using Immutable Types in PHP

Not a Medium member yet? Click here to access this article for FREE!

Photo by Clark Tibbs on Unsplash

Introduction

Immutable types in PHP are objects whose state cannot be changed after creation. This paradigm helps maintain consistency, prevent bugs, and improve application reliability. Immutable objects simplify reasoning about state, reduce complexity, and enhance thread-safety, particularly in concurrent applications.

Benefits of Immutable Types

• Predictability: Immutable objects have consistent states throughout their lifecycle.
• Thread-safety: Easier concurrent programming without locks or synchronization.
• Cacheability: Easily cached and reused without unexpected side-effects.
• Reduced side-effects: Improves maintainability and readability.

Mutable vs Immutable Types

Mutable objects can change their internal state, whereas immutable objects cannot. Mutable types may introduce unexpected side-effects and require careful management, especially in concurrent environments. Immutable types avoid these pitfalls, offering predictability and easier debugging.

// Mutable
$user = new User();
$user->setName('John');
$user->setName('Jane'); // Mutates original…