60 lines
2 KiB
Markdown
60 lines
2 KiB
Markdown
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---
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date: 2025-06-23
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title: Giving things descriptive names
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permalink: /daily/2025/06/23/giving-things-descriptive-names
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---
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An approach I like to use when writing code is value objects, and it was great to see a recent talk by Dan Leech (past guest on the [Beyond Blocks podcast][podcast]) about them at a recent PHP meetup.
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To quote from Dan's talk - "value objects are objects that represent a value".
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They are simple classes that give a meaningful name to a value.
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For example, I could write this value object to represent a railway station code:
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```php
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readonly final class StationCode {
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public function __construct(public string $value) {
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assert(strlen($value) === 3);
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}
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}
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```
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Now, instead of referencing a generic `string` type, I can reference a `StationCode` object.
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This makes the code more readable and easier to understand.
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In this case, I can also validate the string is in the correct format so I know that anywhere a `StationCode` object is used, its values are the correct format and this is done in a single place.
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I can also take this a step further and introduce a `Journey` value object that represents a journey between two stations:
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```
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readonly final class Journey {
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public function __construct(
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public StationCode $origin,
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public StationCode $destination,
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) {
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}
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}
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```
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In this case, a journey always has two stations - an origin and a destination.
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Creating an object to represent this gives it a name, but also prevents data clumping - where groups of variables are passed around together.
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These are two examples from my recent code, but I could find many others.
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And that's one reason why I like value objects - they are so easy and quick to use.
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If you haven't before, try introducing value objects into your code.
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If you already do, reply and tell me about some of the use cases you've found for them.
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You can see the slides from Dan's presentation at <https://www.dantleech.com/slides/2025/dpc-php-value-objects-and-you/presentation.html>.
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[podcast]: /podcast/6-dan-leech-php-tui
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