--- /dev/null
+<?php
+
+namespace Drupal\toolbar\Ajax;
+
+use Drupal\Core\Ajax\CommandInterface;
+
+/**
+ * Defines an AJAX command that sets the toolbar subtrees.
+ */
+class SetSubtreesCommand implements CommandInterface {
+
+ /**
+ * The toolbar subtrees.
+ *
+ * @var array
+ */
+ protected $subtrees;
+
+ /**
+ * Constructs a SetSubtreesCommand object.
+ *
+ * @param array $subtrees
+ * The toolbar subtrees that will be set.
+ */
+ public function __construct($subtrees) {
+ $this->subtrees = $subtrees;
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public function render() {
+ return [
+ 'command' => 'setToolbarSubtrees',
+ 'subtrees' => array_map('strval', $this->subtrees),
+ ];
+ }
+
+}