New: Add backend helper

Carbon.Backend.language(): Return interface language
Carbon.Backend.translate(): Translate string in the interface language

Classes/EelHelper/BackendHelper.php

@@ -0,0 +1,96 @@
+<?php
+
+namespace Carbon\Eel\EelHelper;
+
+use Neos\Eel\ProtectedContextAwareInterface;
+use Neos\Flow\Annotations as Flow;
+use Neos\Flow\Exception;
+use Neos\Flow\I18n\EelHelper\TranslationHelper;
+use Neos\Neos\Service\UserService;
+
+class BackendHelper implements ProtectedContextAwareInterface
+{
+
+    const I18N_LABEL_ID_PATTERN = '/^[a-z0-9]+\.(?:[a-z0-9][\.a-z0-9]*)+:[a-z0-9.]+:.+$/i';
+
+    /**
+     * @Flow\Inject
+     * @var UserService
+     */
+    protected $userService;
+
+    /**
+     * @Flow\Inject
+     * @var TranslationHelper
+     */
+    protected $translationHelper;
+
+    /**
+     * Returns the language from the interface
+     *
+     * @return string
+     */
+    public function language(): string
+    {
+        return $this->userService->getInterfaceLanguage();
+    }
+
+    /**
+     * Get the translated value for an id or original label in the interface language
+     * 
+     * @param string $id
+     * @param string|null $originalLabel
+     * @param array $arguments
+     * @param string $source
+     * @param string|null $package
+     * @param integer|null $quantity
+     * @param string|null $locale
+     * @return string
+     * @throws Exception
+     */
+    public function translate($id, $originalLabel = null, array $arguments = [], $source = 'Main', $package = null, $quantity = null, $locale = null): string
+    {
+        if ($locale === null) {
+            $locale = $this->userService->getInterfaceLanguage();
+        }
+
+        if (
+            $originalLabel === null &&
+            $arguments === [] &&
+            $source === 'Main' &&
+            $package === null &&
+            $quantity === null
+        ) {
+            return preg_match(self::I18N_LABEL_ID_PATTERN, $id) === 1 ? $this->translateByShortHandString($id, $locale) : $id;
+        }
+
+        return $this->translationHelper->translate($id, $originalLabel, $arguments, $source, $package, $quantity, $locale);
+    }
+
+    /**
+     * @param string $shortHandString
+     * @return string
+     * @throws Exception
+     */
+    protected function translateByShortHandString($shortHandString, $locale)
+    {
+        $shortHandStringParts = explode(':', $shortHandString);
+        if (count($shortHandStringParts) === 3) {
+            list($package, $source, $id) = $shortHandStringParts;
+            return $this->translationHelper->translate($id, null, [], $source, $package, null, $locale);
+        }
+
+        throw new \InvalidArgumentException(sprintf('The translation shorthand string "%s" has the wrong format', $shortHandString), 1613464966);
+    }
+
+    /**
+     * All methods are considered safe
+     *
+     * @param string $methodName
+     * @return boolean
+     */
+    public function allowsCallOfMethod($methodName)
+    {
+        return true;
+    }
+}

Configuration/Settings.yaml

@@ -6,6 +6,7 @@ Neos:
       Carbon.FileContent: 'Carbon\Eel\EelHelper\FileContentHelper'
       Carbon.Array: 'Carbon\Eel\EelHelper\ArrayHelper'
       Carbon.Number: 'Carbon\Eel\EelHelper\NumberHelper'
+      Carbon.Backend: 'Carbon\Eel\EelHelper\BackendHelper'
   Neos:
     fusion:
       autoInclude:

README.md

@@ -375,6 +375,29 @@ Format a localized number with grouped thousands
 -   `decimals` (integer, optional) Sets the number of decimal points, defaults to `0`
 -   `locale` (string, optional) String locale - example (de_DE|en|ru_RU)
 
+## Backend Helper
+
+### `Carbon.Backend.language()`
+
+Returns the language from the interface
+
+### `Carbon.Backend.translate(id, originalLabel, arguments, source, package, quantity, locale)`
+
+Get the translated value (in the language of the interface) for an id or original label. If only id is set and contains a translation shorthand string, translate according to that shorthand.
+
+In all other cases:  
+Replace all placeholders with corresponding values if they exist in the translated label.
+
+-   `id` (string) Id to use for finding translation (trans-unit id in XLIFF)
+-   `originalLabel` (string, optional) The original translation value (the untranslated source string)
+-   `arguments` (array, optional) Array of numerically indexed or named values to be inserted into placeholders
+-   `source` (string, optional) Name of file with translations
+-   `package` (string, optional) Target package key
+-   `quantity` (mixed, optional) A number to find plural form for (float or int), NULL to not use plural forms
+-   `locale` (string, optional) An identifier of locale to use (NULL for use the interface language)
+
+Returns the ranslated label or source label / ID key
+
 ## Installation
 
 Carbon.Eel is available via packagist. Just run