Add 'children' filter

src/TwigExtension.php

@@ -69,6 +69,7 @@ class TwigExtension extends \Twig_Extension {
       new \Twig_SimpleFilter('truncate', [$this, 'truncate']),
       new \Twig_SimpleFilter('view', [$this, 'view']),
       new \Twig_SimpleFilter('with', [$this, 'with']),
+      new \Twig_SimpleFilter('children', [$this, 'children']),
     ];
     // PHP filter should be enabled in settings.php file.
     if (Settings::get('twig_tweak_enable_php_filter')) {
@@ -717,6 +718,22 @@ class TwigExtension extends \Twig_Extension {
     return $build;
   }
 
+  /**
+   * Filters out the children of a render array, optionally sorted by weight.
+   *
+   * @param array $build
+   *   The render array whose children are to be filtered.
+   * @param bool $sort
+   *   Boolean to indicate whether the children should be sorted by weight.
+   *
+   * @return array
+   *   The element's children.
+   */
+  public function children(array $build, $sort = FALSE) {
+    $keys = Element::children($build, $sort);
+    return array_intersect_key($build, array_flip($keys));
+  }
+
   /**
    * Returns a render array for entity, field list or field item.
    *

tests/src/Functional/TwigTweakTest.php

@@ -270,6 +270,10 @@ class TwigTweakTest extends BrowserTestBase {
     $xpath = '//div[@class = "tt-with"]/b[text() = "Example"]';
     $this->assertByXpath($xpath);
 
+    // Test 'children'.
+    $xpath = '//div[@class = "tt-children" and text() = "doremi"]';
+    $this->assertByXpath($xpath);
+
     // Test node view.
     $xpath = '//div[@class = "tt-node-view"]/article[contains(@class, "node--view-mode-default")]/h2[a/span[text() = "Beta"]]';
     $xpath .= '/following-sibling::footer[//h4[text() = "Member for"]]';

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

@@ -56,6 +56,20 @@
   <div class="tt-check-markup">{{ '<b>bold</b> <strong>strong</strong>' | check_markup('twig_tweak_test') }}</div>
   <div class="tt-truncate">{{ 'Hello world!'|truncate(10, true, true) }}</div>
   <div class="tt-with">{{ {'#markup':'Example'}|with('#prefix', '<b>')|with('#suffix', '</b>') }}</div>
+  <div class="tt-children">
+    {%-
+      set build = {
+        're': {'#markup': 're'},
+        '#sol':  {'#markup': '#sol'},
+        'mi': {'#markup': 'mi'},
+        '#fa': {'#markup': '#fa'},
+        'do':  {'#markup': 'do', '#weight': -10},
+      }
+    -%}
+    {%- for value in build|children(true) -%}
+      {{- value -}}
+    {%- endfor -%}
+  </div>
   <div class="tt-node-view">{{ node|view }}</div>
   <div class="tt-field-list-view">{{ node.title|view }}</div>
   <div class="tt-field-item-view">{{ node.title[0]|view }}</div>