[FEATURE] add eelcondition for loaded extensions

Signed-off-by: Kay Strobach <[email protected]>

Classes/ExpressionLanguage/ConditionProvider.php

@@ -0,0 +1,20 @@
+<?php
+declare(strict_types = 1);
+
+namespace KayStrobach\Themes\ExpressionLanguage;
+
+use TYPO3\CMS\Core\ExpressionLanguage\AbstractProvider;
+use TYPO3\CMS\Core\Utility\GeneralUtility;
+
+/**
+ * ConditionProvider
+ */
+class ConditionProvider extends AbstractProvider
+{
+    public function __construct()
+    {
+        $this->expressionLanguageVariables = [
+            'extension' => GeneralUtility::makeInstance(ExtensionCondition::class)
+        ];
+    }
+}

Classes/ExpressionLanguage/ExtensionCondition.php

@@ -0,0 +1,18 @@
+<?php
+declare(strict_types = 1);
+
+namespace KayStrobach\Themes\ExpressionLanguage;
+
+use TYPO3\CMS\Core\Utility\ExtensionManagementUtility;
+
+class ExtensionCondition
+{
+    /**
+     * @param string $extensionKey
+     * @return bool
+     */
+    public function isLoaded($extensionKey): bool
+    {
+        return ExtensionManagementUtility::isLoaded($extensionKey);
+    }
+}

Configuration/ExpressionLanguage.php

@@ -0,0 +1,6 @@
+<?php
+return [
+    'typoscript' => [
+        KayStrobach\Themes\ExpressionLanguage\ConditionProvider::class
+    ]
+];