Add HasToggleButton::class trait. (#178)

src/Attribute/Component/HasToggleButton.php

@@ -0,0 +1,31 @@
+<?php
+
+declare(strict_types=1);
+
+namespace PHPForge\Html\Attribute\Component;
+
+use PHPForge\Html\Helper\Encode;
+use PHPForge\Widget\ElementInterface;
+
+/**
+ * Is used by widgets that implement the toggle button method.
+ */
+trait HasToggleButton
+{
+    protected string $toggleButton = '';
+
+    /**
+     * Set the button toogle for the toggle.
+     *
+     * @param ElementInterface|string ...$values The button content.
+     *
+     * @return static A new instance of the current class with the specified toggle button.
+     */
+    public function toggleButton(string|ElementInterface ...$values): static
+    {
+        $new = clone $this;
+        $new->toggleButton = Encode::santizeXSS(...$values);
+
+        return $new;
+    }
+}

tests/Attribute/Component/HasToggleButtonTest.php

@@ -0,0 +1,20 @@
+<?php
+
+declare(strict_types=1);
+
+namespace PHPForge\Html\Tests\Attribute\Component;
+
+use PHPForge\Html\Attribute\Component\HasToggleButton;
+use PHPUnit\Framework\TestCase;
+
+final class HasToggleButtonTest extends TestCase
+{
+    public function testImmutability(): void
+    {
+        $instance = new class () {
+            use HasToggleButton;
+        };
+
+        $this->assertNotSame($instance, $instance->toggleButton(''));
+    }
+}