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[Form] Example of customizing EnumType labels #17149

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[Form] Example of customizing EnumType labels #17149

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34 changes: 34 additions & 0 deletions reference/forms/types/enum.rst
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Original file line number Diff line number Diff line change
Expand Up @@ -56,6 +56,40 @@ This will display a ``<select>`` tag with the three possible values defined in
the ``TextAlign`` enum. Use the `expanded`_ and `multiple`_ options to display
these values as ``<input type="checkbox">`` or ``<input type="radio">``.

Since the label displayed in the ``<select>`` options is the enum name, you might sometimes
want more flexibility as PHP strongly restricts the usable characters for those.
You could do this by implementing a function in your enum class which returns a label
or even a translation string for each possible enum::

// src/Config/TextAlign.php
namespace App\Config;

enum TextAlign: string
{
case Left = 'Left/Start aligned';
case Center = 'Center/Middle aligned';
case Right = 'Right/End aligned';

public function label(): string
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Adding this method to the enum class starts mixing data and presentation which I would not advise. Let's configure the choice label using a closure instead (see comment below).

{
return match ($this) {
self::Left => 'text_align.left.label',
self::Center => 'text_align.center.label',
self::Right => 'text_align.right.label',
};
}
}

You can then use the ``choice_label`` option of ``EnumType`` with a function that
returns the label::

->add('textAlign', EnumType::class, [
'class' => TextAlign::class,
'choice_label' => static function (TextAlign $choice): string {
return $choice->label();
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Suggested change
return $choice->label();
return match ($choice) {
TextAlign::Left => 'text_align.left.label',
TextAlign::Center => 'text_align.center.label',
TextAlign::Right => 'text_align.right.label',
};

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This would work if you only needed to display the labels in your form, but if you also need them to appear anywhere else in your application I think adding a method in the enum class is a better solution. I don't think adding presentation methods in enum classes is a bad practice.

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If I had different places where I needed the label, I would go with a separate class that maps enum instances to labels to be honest.

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That might be a way to do it but maybe a bit overkill. Even the PHP documentation suggests adding a label method in enum classes in their examples : https://www.php.net/manual/fr/language.enumerations.examples.php

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I don't know what to say here. I think both of you gave good reasons to do opposite things.

Let's ask @wouterj and @OskarStark. Thanks!

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@wouterj wouterj Oct 6, 2022 •
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I agree with @xabbuh here. I understand your point, @robinbrisa, and it is also proven by the official PHP docs.

However, I would say that an enum can ship a generic presentation layer. The labels provided in this example indirectly couple the Enum's presentation layer to the Symfony Translation component - without it, the labels render worse human readable than their default string representation from the BackedEnum.
In that case, I would favor to keep the enum decoupled from Symfony Translation and handle the presentation in the layer that is responsible for mapping between Symfony Translation and the Enum, which is this function :)

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Another way to see it would be to have MyEnum::getLabel() and/or MyEnum::getTranslationKey() to make it more reusable with respect for different layers.
However for the docs I agree this callable is a good way to go.

},
])
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Suggested change
])
]);


Field Options
-------------

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