Added transliteration filter.

src/TwigExtension.php

@@ -47,6 +47,7 @@ class TwigExtension extends \Twig_Extension {
       new \Twig_SimpleFilter('token_replace', [$this, 'tokenReplaceFilter']),
       new \Twig_SimpleFilter('preg_replace', [$this, 'pregReplaceFilter']),
       new \Twig_SimpleFilter('image_style', [$this, 'imageStyle']),
+      new \Twig_SimpleFilter('transliterate', [$this, 'transliterate']),
     ];
     // PHP filter should be enabled in settings.php file.
     if (Settings::get('twig_tweak_enable_php_filter')) {
@@ -382,6 +383,30 @@ class TwigExtension extends \Twig_Extension {
     }
   }
 
+  /**
+   * Transliterates text from Unicode to US-ASCII.
+   *
+   * @param string $string
+   *   The string to transliterate.
+   * @param string $langcode
+   *   (optional) The language code of the language the string is in. Defaults
+   *   to 'en' if not provided. Warning: this can be unfiltered user input.
+   * @param string $unknown_character
+   *   (optional) The character to substitute for characters in $string without
+   *   transliterated equivalents. Defaults to '?'.
+   * @param int $max_length
+   *   (optional) If provided, return at most this many characters, ensuring
+   *   that the transliteration does not split in the middle of an input
+   *   character's transliteration.
+   *
+   * @return string
+   *   $string with non-US-ASCII characters transliterated to US-ASCII
+   *   characters, and unknown characters replaced with $unknown_character.
+   */
+  public function transliterate($string, $langcode = 'en', $unknown_character = '?', $max_length = NULL) {
+    return \Drupal::transliteration()->transliterate($string, $langcode, $unknown_character, $max_length);
+  }
+
   /**
    * Evaluates a string of PHP code.
    *

tests/src/Functional/TwigTweakTest.php

@@ -148,6 +148,10 @@ class TwigTweakTest extends BrowserTestBase {
     // Test image style.
     $xpath = '//div[@class = "tt-image-style" and contains(text(), "styles/thumbnail/public/images/ocean.jpg")]';
     $this->assertByXpath($xpath);
+
+    // Test transliteration.
+    $xpath = '//div[@class = "tt-transliterate" and contains(text(), "Privet!")]';
+    $this->assertByXpath($xpath);
   }
 
   /**

tests/twig_tweak_test/templates/twig-tweak-test.html.twig

@@ -37,4 +37,5 @@
   <div class="tt-token-replace">{{ 'Site name: [site:name]' | token_replace }}</div>
   <div class="tt-preg-replace">{{ 'foo' | preg_replace('(foo)', '$1-bar') }}</div>
   <div class="tt-image-style">{{ 'public://images/ocean.jpg' | image_style('thumbnail') }}</div>
+  <div class="tt-transliterate">{{ 'Привет!' | transliterate('ru') }}</div>
 </div>