Add daily email for 2025-02-13

readonly

source/_daily_emails/2025-02-13.md

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+---
+title: Using readonly in PHP
+date: 2025-02-13
+permalink: daily/2025/02/13/readonly
+tags:
+  - software-development
+  - php
+cta: ~
+snippet: |
+  Did you know you can make classes and properties read-only since PHP 8.1?
+---
+
+Since PHP 8.1, properties on PHP classes have been able to be marked as `readonly`.
+
+Once they've been set, they can't be changed or overwritten.
+
+This is great for data transfer objects (DTOs) that you want to be immutable and know the values are the same as when they were set.
+
+Here's an example:
+
+```php
+class MyDto {
+
+  public function __construct(
+    public readonly string $name,
+    public readonly int $age,
+  ) {
+  }
+
+}
+```
+
+I don't need to make the properties private or protected and write getter methods for them.
+
+I can make them public,  knowing the values can't be changed.
+
+## readonly classes
+
+Since PHP 8.2, the entire class can be `readonly`, making the code cleaner and easier to read.
+
+This class does the same as the previous example:
+
+```php
+readonly class MyDto {
+
+  public function __construct(
+    public string $name,
+    public int $age,
+  ) {
+  }
+
+}
+```
+
+## Here's the thing
+
+This is a great example of how the PHP language continues to evolve and improve, and it's been a great way to make it easier to keep my code clean and with fewer bugs.
+
+If you want a way to easily add `readonly` to properties or classes, [take a look at Rector][0] which can automate it for you.
+
+[0]: {{site.url}}/daily/2025/01/31/rector