PHP 8.4 property hooks let properties define get and set behavior for normalization, validation and computed values.
The examples below begin with the core behavior, then move to an application-oriented use.
How PHP 8.4 Property Hooks: Syntax, Validation, and Examples Works
PHP 8.4 property hooks let properties define get and set behavior for normalization, validation and computed values.
Compatibility note: Requires PHP 8.4 or later.
Example 1: Basic Usage
This example uses a small input to make the main behavior visible.
<?php
class Customer { public string $email { set(string $value) { $this->email = strtolower(trim($value)); } } }
$customer = new Customer();
$customer->email = " [email protected] ";
echo $customer->email;Output:
[email protected]PHP 8.4 property hooks let properties define get and set behavior for normalization, validation and computed values.
Example 2: A Different Input
A different set of values shows the same operation in another situation.
<?php
class Inventory { private int $stock = 10; public int $available { get => $this->stock; } }
echo (new Inventory())->available;Output:
10Hooks must preserve invariants; they are incompatible with readonly properties and must not recurse unintentionally.
Practical Example: Applying the Feature
This example shows an application-style use of the feature, with its surrounding setup visible.
<?php
class Temperature { public float $celsius { set(float $value) { if ($value < -273.15) { throw new ValueError("Below absolute zero"); } $this->celsius = $value; } } }
$measurement = new Temperature();
$measurement->celsius = 21.5;
echo $measurement->celsius;Output:
21.5The code is shown for learning. Adjust the class names, inputs and error handling to suit your application.
Important Behavior and Edge Cases
- Hooks must preserve invariants; they are incompatible with readonly properties and must not recurse unintentionally.
- PHP 8.4 property hooks let properties define get and set behavior for normalization, validation and computed values.
- Observe differences in empty inputs, invalid states and optional extension availability where relevant.
Comparison With Related Approaches
| Approach | Important Difference |
|---|---|
PHP 8.4 Property Hooks: Syntax, Validation, and Examples | PHP 8.4 property hooks let properties define get and set behavior for normalization, validation and computed values. |
| Alternative approach | Traditional getters and setters require method calls but may be easier to use for complicated logic. |
Common Beginner Mistakes
| Mistake | Correct Approach |
|---|---|
Ignoring the documented state or precondition of PHP 8.4 Property Hooks: Syntax, Validation, and Examples | Hooks must preserve invariants; they are incompatible with readonly properties and must not recurse unintentionally. |
| Expecting a different type of result | Read the declared return type and distinguish returned values from changes to the source object. |
| Assuming a related API works identically | Traditional getters and setters require method calls but may be easier to use for complicated logic. |
Key Takeaways
- PHP 8.4 property hooks let properties define get and set behavior for normalization, validation and computed values.
- Hooks must preserve invariants; they are incompatible with readonly properties and must not recurse unintentionally.
- Use the example that matches the values, runtime version and dependencies in your application.
PHP 8.4 Property Hooks: Syntax, Validation, and Examples is useful when its behavior matches the data structure and lifecycle of your PHP application. Choose it with a clear understanding of its preconditions and returned values.