Root methods

README.md

@@ -3,6 +3,7 @@
 In Tree you can find a basic but flexible tree data structure for php together with and an handful Builder class, that enables you to build tree in a fluent way.
 
 ## Changelog
+ - 0.2.1 root() and isRoot() methods
  - 0.2.0 Dropped php 5.3 support. Node implemented as a trait.
  - 0.1.2 Added YieldVisitor, to get the yield of the tree
  - 0.1.1 Parent and neighbors methods (thanks to https://github.com/jdeniau)
@@ -80,6 +81,11 @@ $root = (new Node('root'))
 $grandchild->getAncestors(); // Returns [$root, $child]
 ```
 
+### Getting the root of a node
+```php
+$root = $node->root();
+```
+
 ### Getting the neighbors of a node
 ```php
 $root = (new Node('root'))

src/Tree/Node/NodeTrait.php

@@ -177,6 +177,29 @@ public function isLeaf()
         return count($this->children) == 0;
     }
 
+    /**
+     * @return bool
+     */
+    public function isRoot()
+    {
+        return $this->getParent() === null;
+    }
+
+    /**
+     * Find the root of the node
+     *
+     * @return NodeInterface
+     */
+    public function root()
+    {
+        $node = $this;
+
+        while ($parent = $node->getParent())
+            $node = $parent;
+
+        return $node;
+    }
+
     /**
      * {@inheritdoc}
      */

tests/Tree/Node/NodeTest.php

@@ -150,4 +150,23 @@ public function testIsLeaf()
 
         $this->assertFalse($root->isLeaf());
     }
+
+    public function testRoot()
+    {
+        $root = (new Node('root'))
+            ->addChild(
+                (new Node('child'))->addChild($grandchild = new Node('grandchild'))
+            );
+
+        $this->assertSame($root, $grandchild->root());
+    }
+
+    public function testIsRoot()
+    {
+        $root = new Node('root');
+        $root->addChild($child = new Node('child'));
+
+        $this->assertTrue($root->isRoot());
+        $this->assertFalse($child->isRoot());
+    }
 }