PHP Enumeration classes vs fake enumerations what to use.

I am growing to HATE PHP ENUMS. Why? Because if you forget to call ->value you get BS errors about cannot convert object to string. It is just another un-needed step. Enums sounded cool at first but fuq the BS with calling ->value, it is entirely too easy to forget.

Enumeration classes in PHP are a new feature as of version 8.1 Fake enumerations were what we did before this new feature. A fake enumeration was just a class with constants, the syntax to refer to them was the same minus ->value. See my other article if you don’t know what fake PHP enumerations are Php Backed Enums don’t forget to call value

TLDR

Use plain classes with constants if any of the values will repeat. Use Enumerations when each value is always unique. Keep reading to find out WTF I am talking about.

The story

The new Enumeration classes have a limitation on them that each “case” must have an unique value, it is just how it works.
This is only a problem when you are using Enumerations more like the old fake constant enumerations, because you can’t give two cases the same value. If you are using ints you run into this issue more quickly.

Let me show an example.

I have often used this pattern to help eliminate bugs from typing, it also helps you remember what values are possible for something. Below is the values allowed for an image for some sort of upload.

class ImageDataEnum
{
    const HEIGHT = 'height';
    const SIZE_STRING = 'size';
    const IMAGE_URL = 'image_url';
    const WIDTH = 'width';
}

This way I know what values are allowed in the upload and I don’t get errors from typing.This would convert to an Enumeration perfectly.

I have dysgraphia and dyslexia so this is something I fight constantly, it is also why I hate Linux command line. Basically my brain gets the letters out of order sometimes when I type or write or leaves entire letters out or adds them and my eyes don’t see it for some odd reason sometimes. I couldn’t take notes in school because it turned into jibberish word soup.

But I also like to use them to store info that won’t change, like maximum image size. This is a use case that won’t work with PHP Enumerations, probably one of the only ones I can think of.

Bad code

This kind of code won’t work.

enum ImageSizeEnum: int
{

    case BLOG_IMAGE_HEIGHT = 600;
    case BLOG_IMAGE_WIDTH = 600;
    case TWITTER_LARGE_IMAGE_HEIGHT = 600;
    case TWITTER_LARGE_IMAGE_WIDTH = 1200;
    case PROFILE_PICTURE_HEIGHT = 180;
    case PROFILE_PICTURE_WIDTH = 180;
    case PROFILE_THUMB_HEIGHT = 55;
    case PROFILE_THUMB_WIDTH = 55;
    case USER_THUMB_HEIGHT = 150;
    case USER_THUMB_WIDTH = 150;
    case USER_IMAGE_HEIGHT = 600;
    case USER_IMAGE_WIDTH = 600;

}

Notice that while each case has a unique name, they do not have unique values. The code above will give you an error because the values for the cases is repeated. If you are using PHPStorm then it is screaming at you right now with red underlines and error warnings etc. LOLOL

The docs say the following

In PHP, Enums are a special kind of object. The Enum itself is a class, and its possible cases are all single-instance objects of that class. That means Enum cases are valid objects and may be used anywhere an object may be used, including type checks

In order to do what is intended in the code above (a list of constants to be used in code later) this has to be converted back to a class with constants. It looks so similar it is crazy.

Ok code

This code will work.

class ImageSizeEnum
{

    const BLOG_IMAGE_HEIGHT = 600;
    const BLOG_IMAGE_WIDTH = 600;
    const TWITTER_LARGE_IMAGE_HEIGHT = 600;
    const TWITTER_LARGE_IMAGE_WIDTH = 1200;
    const PROFILE_PICTURE_HEIGHT = 180;
    const PROFILE_PICTURE_WIDTH = 180;
    const PROFILE_THUMB_HEIGHT = 55;
    const PROFILE_THUMB_WIDTH = 55;
    const USER_THUMB_HEIGHT = 150;
    const USER_THUMB_WIDTH = 150;
    const USER_IMAGE_HEIGHT = 600;
    const USER_IMAGE_WIDTH = 600;

}

With the fake enum you leave off the ->value part when you need the value as noted in this article. Php Backed Enums don’t forget to call value

Now I can have constants that have the same value and PHP won’t barf errors on me.

You can also do something very similar in Javascript if you are interested check out this article. Faking Enumerations with Vanilla javascript

Summary

So basically if you need to use the same value with a different name, then you need the old fashioned PHP fake enumerations. If your use case has it so that every named case has a unique value then use Enumerations.