Add additional methods (#232)

README.md

@@ -65,6 +65,7 @@ Supports Laravel 5.5+.
 - [Custom Paths](#custom-paths)
 - [Nested Results](#nested-results)
 - [Initial & Recursive Query Constraints](#initial--recursive-query-constraints)
+- [Additional Methods](#additional-methods)
 - [Custom Relationships](#custom-relationships)
 - [Deep Relationship Concatenation](#deep-relationship-concatenation)
 - [Known Issues](#known-issues)
@@ -407,6 +408,24 @@ $tree = User::withQueryConstraint(function (Builder $query) {
  You can also add a custom constraint to only the initial or recursive query using `withInitialQueryConstraint()`/
  `withRecursiveQueryConstraint()`.
 
+#### Additional Methods
+
+The trait also provides methods to check relationships between models:
+
+- `isChildOf(Model $model)`: Checks if the current model is a child of the given model.
+- `isParentOf(Model $model)`: Checks if the current model is a parent of the given model.
+- `getDepthRelatedTo(Model $model)`: Returns the depth of the current model related to the given model.
+
+```php
+$rootUser = User::create(['parent_id' => null]); 
+$firstLevelUser = User::create(['parent_id' => $rootUser->id]); 
+$secondLevelUser = User::create(['parent_id' => $firstLevelUser->id]);  
+
+$isChildOf = $secondLevelUser->isChildOf($firstLevelUser); // Output: true
+$isParentOf = $rootUser->isParentOf($firstLevelUser); // Output: true
+$depthRelatedTo = $secondLevelUser->getDepthRelatedTo($rootUser); // Output: 2
+```
+
 #### Custom Relationships
 
 You can also define custom relationships to retrieve related models recursively.

src/Eloquent/Traits/HasAdjacencyList.php

@@ -16,6 +16,7 @@ trait HasAdjacencyList
 {
     use HasOfDescendantsRelationships;
     use HasQueryConstraints;
+    use HasRecursiveRelationshipHelpers;
     use HasRecursiveRelationshipScopes;
 
     /**

src/Eloquent/Traits/HasRecursiveRelationshipHelpers.php

@@ -0,0 +1,50 @@
+<?php
+
+namespace Staudenmeir\LaravelAdjacencyList\Eloquent\Traits;
+
+use Illuminate\Database\Eloquent\Model;
+
+trait HasRecursiveRelationshipHelpers
+{
+    /**
+     * Determine if the model is a child of the given model.
+     *
+     * @param \Illuminate\Database\Eloquent\Model $model
+     * @return bool
+     */
+    public function isChildOf(Model $model): bool
+    {
+        return $this->parent ? $this->parent->is($model) : false;
+    }
+
+    /**
+     * Determine if the model is the parent of the given model.
+     *
+     * @param \Illuminate\Database\Eloquent\Model $model
+     * @return bool
+     */
+    public function isParentOf(Model $model): bool
+    {
+        return $this->children->contains($model);
+    }
+
+    /**
+     * Get the depth of the model related to the given model.
+     *
+     * @param \Illuminate\Database\Eloquent\Model $model
+     * @return int|null
+     */
+    public function getDepthRelatedTo(Model $model): ?int
+    {
+        $thisModel = $this->bloodline->find($this);
+        $relatedModel = $this->bloodline->find($model);
+
+        if ($thisModel && $relatedModel) {
+            $depthName = $this->getDepthName();
+
+            return $thisModel->$depthName - $relatedModel->$depthName;
+        }
+
+        return null;
+    }
+}

tests/Tree/EloquentTest.php

@@ -191,6 +191,27 @@ public function testScopeDepthFirstWithStringKey()
         $this->assertEquals(['a', 'b', 'c', 'd'], $categories->pluck('id')->all());
     }
 
+    public function testIsChildOf()
+    {
+        $this->assertTrue(User::find(5)->isChildOf(User::find(2)));
+        $this->assertFalse(User::find(5)->isChildOf(User::find(1)));
+        $this->assertFalse(User::find(1)->isChildOf(User::find(2)));
+    }
+
+    public function testIsParentOf()
+    {
+        $this->assertTrue(User::find(2)->isParentOf(User::find(5)));
+        $this->assertFalse(User::find(1)->isParentOf(User::find(5)));
+        $this->assertFalse(User::find(2)->isParentOf(User::find(1)));
+    }
+
+    public function testGetDepthRelatedTo()
+    {
+        $this->assertEquals(2, User::find(5)->getDepthRelatedTo(User::find(1)));
+        $this->assertEquals(-2, User::find(1)->getDepthRelatedTo(User::find(5)));
+        $this->assertNull(User::find(4)->getDepthRelatedTo(User::find(5)));
+    }
+
     public function testWithInitialQueryConstraint()
     {
         $users = User::withInitialQueryConstraint(function (Builder $query) {