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|
``html_cva``
============
.. versionadded:: 3.12
The ``html_cva`` function was added in Twig 3.12.
`CVA (Class Variant Authority)`_ is a concept from the JavaScript world and used
by the well-known `shadcn/ui`_ library.
The CVA concept is used to render multiple variations of components, applying
a set of conditions and recipes to dynamically compose CSS class strings (color, size, etc.),
to create highly reusable and customizable templates.
The concept of CVA is powered by a ``html_cva()`` Twig
function where you define ``base`` classes that should always be present and then different
``variants`` and the corresponding classes:
.. code-block:: html+twig
{# templates/alert.html.twig #}
{% set alert = html_cva(
base: 'alert',
variants: {
color: {
blue: 'bg-blue',
red: 'bg-red',
green: 'bg-green',
},
size: {
sm: 'text-sm',
md: 'text-md',
lg: 'text-lg',
}
}
) %}
<div class="{{ alert.apply({color, size}, class) }}">
...
</div>
Then use the ``color`` and ``size`` variants to select the needed classes:
.. code-block:: twig
{# index.html.twig #}
{{ include('alert.html.twig', {'color': 'blue', 'size': 'md'}) }}
// class="alert bg-blue text-md"
{{ include('alert.html.twig', {'color': 'green', 'size': 'sm'}) }}
// class="alert bg-green text-sm"
{{ include('alert.html.twig', {'color': 'red', 'class': 'flex items-center justify-center'}) }}
// class="alert bg-red flex items-center justify-center"
CVA and Tailwind CSS
--------------------
CVA work perfectly with Tailwind CSS. The only drawback is that you can have class conflicts.
To "merge" conflicting classes together and keep only the ones you need, use the
``tailwind_merge()`` filter from `tales-from-a-dev/twig-tailwind-extra`_
with the ``html_cva()`` function:
.. code-block:: terminal
$ composer require tales-from-a-dev/twig-tailwind-extra
.. code-block:: html+twig
{% set alert = html_cva(
// ...
) %}
<div class="{{ alert.apply({color, size}, class)|tailwind_merge }}">
...
</div>
Compound Variants
-----------------
You can define compound variants. A compound variant is a variant that applies
when multiple other variant conditions are met:
.. code-block:: html+twig
{% set alert = html_cva(
base: 'alert',
variants: {
color: {
blue: 'bg-blue',
red: 'bg-red',
green: 'bg-green',
},
size: {
sm: 'text-sm',
md: 'text-md',
lg: 'text-lg',
}
},
compoundVariants: [{
// if color = red AND size = (md or lg), add the `font-bold` class
color: ['red'],
size: ['md', 'lg'],
class: 'font-bold'
}]
) %}
<div class="{{ alert.apply({color, size}) }}">
...
</div>
{# index.html.twig #}
{{ include('alert.html.twig', {color: 'red', size: 'lg'}) }}
// class="alert bg-red text-lg font-bold"
{{ include('alert.html.twig', {color: 'green', size: 'sm'}) }}
// class="alert bg-green text-sm"
{{ include('alert.html.twig', {color: 'red', size: 'md'}) }}
// class="alert bg-green text-md font-bold"
Default Variants
----------------
If no variants match, you can define a default set of classes to apply:
.. code-block:: html+twig
{% set alert = html_cva(
base: 'alert',
variants: {
color: {
blue: 'bg-blue',
red: 'bg-red',
green: 'bg-green',
},
size: {
sm: 'text-sm',
md: 'text-md',
lg: 'text-lg',
},
rounded: {
sm: 'rounded-sm',
md: 'rounded-md',
lg: 'rounded-lg',
}
},
defaultVariant: {
rounded: 'md',
}
) %}
<div class="{{ alert.apply({color, size}) }}">
...
</div>
{# index.html.twig #}
{{ include('alert.html.twig', {color: 'red', size: 'lg'}) }}
// class="alert bg-red text-lg rounded-md"
.. note::
The ``html_cva`` function is part of the ``HtmlExtension`` which is not
installed by default. Install it first:
.. code-block:: bash
$ composer require twig/html-extra
Then, on Symfony projects, install the ``twig/extra-bundle``:
.. code-block:: bash
$ composer require twig/extra-bundle
Otherwise, add the extension explicitly on the Twig environment::
use Twig\Extra\Html\HtmlExtension;
$twig = new \Twig\Environment(...);
$twig->addExtension(new HtmlExtension());
This function works best when used with `TwigComponent`_.
.. _`CVA (Class Variant Authority)`: https://cva.style/docs/getting-started/variants
.. _`shadcn/ui`: https://ui.shadcn.com
.. _`tales-from-a-dev/twig-tailwind-extra`: https://github.com/tales-from-a-dev/twig-tailwind-extra
.. _`TwigComponent`: https://symfony.com/bundles/ux-twig-component/current/index.html
|
