[Twig] Allow nested attributes

src/TwigComponent/CHANGELOG.md

@@ -1,5 +1,9 @@
 # CHANGELOG
 
+## 2.17.0
+
+-   Add nested attribute support #1405
+
 ## 2.16.0
 
 -   Introduce CVA to style TwigComponent #1416

src/TwigComponent/doc/index.rst

@@ -1058,6 +1058,63 @@ Exclude specific attributes:
       My Component!
     </div>
 
+Nested Attributes
+~~~~~~~~~~~~~~~~~
+
+.. versionadded:: 2.17
+
+    The Nested Attributes feature was added in TwigComponents 2.17.
+
+You can have attributes that aren't meant to be used on the *root* element
+but one of its *descendants*. This is useful for, say, a dialog component where
+you want to allow customizing the attributes of the dialog's content, title,
+and footer. Here's an example of this:
+
+.. code-block:: html+twig
+
+    {# templates/components/Dialog.html.twig #}
+    <div{{ attributes }}>
+        <div{{ attributes.nested('title') }}>
+            {% block title %}Default Title{% endblock %}
+        </div>
+        <div{{ attributes.nested('body') }}>
+            {% block content %}{% endblock %}
+        </div>
+        <div{{ attributes.nested('footer') }}>
+            {% block footer %}Default Footer{% endblock %}
+        </div>
+    </div>
+
+    {# render #}
+    <twig:Dialog class="foo" title:class="bar" body:class="baz" footer:class="qux">
+        Some content
+    </twig:MyDialog>
+
+    {# output #}
+    <div class="foo">
+        <div class="bar">
+            Default Title
+        </div>
+        <div class="baz">
+            Some content
+        </div>
+        <div class="qux">
+            Default Footer
+        </div>
+    </div>
+
+The nesting is recursive so you could potentially do something like this:
+
+.. code-block:: html+twig
+
+    <twig:Form
+        :form="form"
+        class="ui-form"
+        row:class="ui-form-row"
+        row:label:class="ui-form-label"
+        row:widget:class="ui-form-widget"
+    />
+
 Component with Complex Variants (CVA)
 -------------------------------------
 

src/TwigComponent/src/ComponentAttributes.php

@@ -19,8 +19,10 @@
  *
  * @immutable
  */
-final class ComponentAttributes implements \IteratorAggregate, \Countable
+final class ComponentAttributes implements \Stringable, \IteratorAggregate, \Countable
 {
+    private const NESTED_REGEX = '#^([\w-]+):(.+)$#';
+
     /** @var array<string,true> */
     private array $rendered = [];
 
@@ -39,6 +41,10 @@ public function __toString(): string
                 fn (string $key) => !isset($this->rendered[$key])
             ),
             function (string $carry, string $key) {
+                if (preg_match(self::NESTED_REGEX, $key)) {
+                    return $carry;
+                }
+
                 $value = $this->attributes[$key];
 
                 if ($value instanceof \Stringable) {
@@ -196,6 +202,19 @@ public function remove($key): self
         return new self($attributes);
     }
 
+    public function nested(string $namespace): self
+    {
+        $attributes = [];
+
+        foreach ($this->attributes as $key => $value) {
+            if (preg_match(self::NESTED_REGEX, $key, $matches) && $namespace === $matches[1]) {
+                $attributes[$matches[2]] = $value;
+            }
+        }
+
+        return new self($attributes);
+    }
+
     public function getIterator(): \Traversable
     {
         return new \ArrayIterator($this->attributes);

src/TwigComponent/tests/Fixtures/templates/components/JustAttributes.html.twig

@@ -0,0 +1 @@
+<div{{ attributes }}/>

src/TwigComponent/tests/Fixtures/templates/components/NestedAttributes.html.twig

@@ -0,0 +1,7 @@
+<main{{ attributes }}>
+    <div{{ attributes.nested('title') }}>
+        <span{{ attributes.nested('title').nested('span') }}>
+            {{ component('JustAttributes', [...attributes.nested('inner')]) }}
+        </span>
+    </div>
+</main>

src/TwigComponent/tests/Integration/ComponentExtensionTest.php

@@ -263,6 +263,84 @@ public function testComponentWithClassMerge(): void
         $this->assertStringContainsString('class="alert alert-red alert-lg font-semibold rounded-md dark:bg-gray-600 flex p-4"', $output);
     }
 
+    public function testRenderingComponentWithNestedAttributes(): void
+    {
+        $output = $this->renderComponent('NestedAttributes');
+
+        $this->assertSame(<<<HTML
+            <main>
+                <div>
+                    <span>
+                        <div/>
+
+                    </span>
+                </div>
+            </main>
+            HTML,
+            trim($output)
+        );
+
+        $output = $this->renderComponent('NestedAttributes', [
+            'class' => 'foo',
+            'title:class' => 'bar',
+            'title:span:class' => 'baz',
+        ]);
+
+        $this->assertSame(<<<HTML
+            <main class="foo">
+                <div class="bar">
+                    <span class="baz">
+                        <div/>
+
+                    </span>
+                </div>
+            </main>
+            HTML,
+            trim($output)
+        );
+    }
+
+    public function testRenderingHtmlSyntaxComponentWithNestedAttributes(): void
+    {
+        $output = self::getContainer()
+            ->get(Environment::class)
+            ->createTemplate('<twig:NestedAttributes />')
+            ->render()
+        ;
+
+        $this->assertSame(<<<HTML
+            <main>
+                <div>
+                    <span>
+                        <div/>
+
+                    </span>
+                </div>
+            </main>
+            HTML,
+            trim($output)
+        );
+
+        $output = self::getContainer()
+            ->get(Environment::class)
+            ->createTemplate('<twig:NestedAttributes class="foo" title:class="bar" title:span:class="baz" inner:class="foo" />')
+            ->render()
+        ;
+
+        $this->assertSame(<<<HTML
+            <main class="foo">
+                <div class="bar">
+                    <span class="baz">
+                        <div class="foo"/>
+
+                    </span>
+                </div>
+            </main>
+            HTML,
+            trim($output)
+        );
+    }
+
     private function renderComponent(string $name, array $data = []): string
     {
         return self::getContainer()->get(Environment::class)->render('render_component.html.twig', [

src/TwigComponent/tests/Unit/ComponentAttributesTest.php

@@ -244,4 +244,18 @@ public function testCanCheckIfAttributeExists(): void
 
         $this->assertTrue($attributes->has('foo'));
     }
+
+    public function testNestedAttributes(): void
+    {
+        $attributes = new ComponentAttributes([
+            'class' => 'foo',
+            'title:class' => 'bar',
+            'title:span:class' => 'baz',
+        ]);
+
+        $this->assertSame(' class="foo"', (string) $attributes);
+        $this->assertSame(' class="bar"', (string) $attributes->nested('title'));
+        $this->assertSame(' class="baz"', (string) $attributes->nested('title')->nested('span'));
+        $this->assertSame('', (string) $attributes->nested('invalid'));
+    }
 }