diff --git a/twig_tweak.api.php b/twig_tweak.api.php
index 0965818..a920c3d 100644
--- a/twig_tweak.api.php
+++ b/twig_tweak.api.php
@@ -24,19 +24,13 @@ use Twig\TwigTest;
  */
 function hook_twig_tweak_functions_alter(array &$functions): void {
   // A simple way to implement lazy loaded global variables.
-  $functions[] = new TwigFunction('var', function (string $name) {
-    $value = NULL;
-    switch ($name) {
-      case 'foo':
-        $value = 'Foo';
-        break;
-
-      case 'bar':
-        $value = 'Bar';
-        break;
-    }
-    return $value;
-  });
+  $callback = static fn (string $name): ?string =>
+    match ($name) {
+      'foo' => 'Foo',
+      'bar' => 'Bar',
+      default => NULL,
+    };
+  $functions[] = new TwigFunction('var', $callback);
 }
 
 /**
@@ -58,9 +52,9 @@ function hook_twig_tweak_filters_alter(array &$filters): void {
  *   Twig tests to alter.
  */
 function hook_twig_tweak_tests_alter(array &$tests): void {
-  $tests[] = new TwigTest('outdated', function (NodeInterface $node): bool {
-    return \Drupal::time()->getRequestTime() - $node->getCreatedTime() > 3600 * 24 * 365;
-  });
+  $callback = static fn (NodeInterface $node): bool =>
+    \Drupal::time()->getRequestTime() - $node->getCreatedTime() > 3600 * 24 * 365;
+  $tests[] = new TwigTest('outdated', $callback);
 }
 
 /**