Implementend collection nest

cakephp · Jan 19, 2014 · 41ddf1a · 41ddf1a
1 parent 4de65e7
commit 41ddf1a
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diff --git a/src/Collection/CollectionTrait.php b/src/Collection/CollectionTrait.php
@@ -15,6 +15,7 @@
 namespace Cake\Collection;
 
 use AppendIterator;
+use ArrayObject;
 use Cake\Collection\Collection;
 use Cake\Collection\Iterator\ExtractIterator;
 use Cake\Collection\Iterator\FilterIterator;
@@ -701,6 +702,54 @@ public function combine($keyPath, $valuePath, $groupPath = null) {
 		return new Collection(new MapReduce($this, $mapper, $reducer));
 	}
 
+/**
+ * Returns a new collection where the values are nested in a tree-like structure
+ * based on an id property path and a parent id property path.
+ *
+ * @param callable|string $idPath the column name path to use for determining
+ * whther an element is parent of another
+ * @param callable|string $parentPath the column name path to use for determining
+ * whther an element is child of another
+ * @return \Cake\Collection\Collection
+ */
+	public function nest($idPath, $parentPath) {
+		$parents = [];
+		$idPath = $this->_propertyExtractor($idPath);
+		$parentPath = $this->_propertyExtractor($parentPath);
+		$isObject = !is_array($this->first());
+
+		$mapper = function($row, $key, $mapReduce) use (&$parents, $idPath, $parentPath) {
+			$row['children'] = [];
+			$id = $idPath($row, $key);
+			$parentId = $parentPath($row, $key);
+			$parents[$id] =& $row;
+			$mapReduce->emitIntermediate($id, $parentId);
+		};
+
+		$reducer = function($values, $key, $mapReduce) use (&$parents, $isObject) {
+			if (empty($key) || !isset($parents[$key])) {
+				foreach ($values as $id) {
+					$parents[$id] = $isObject ? $parents[$id] : new ArrayObject($parents[$id]);
+					$mapReduce->emit($parents[$id]);
+				}
+				return;
+			}
+
+			foreach ($values as $id) {
+				$parents[$key]['children'][] =& $parents[$id];
+			}
+		};
+
+		$collection = new MapReduce($this, $mapper, $reducer);
+		if (!$isObject) {
+			$collection = (new Collection($collection))->map(function($value) {
+				return (array)$value;
+			});
+		}
+
+		return new Collection($collection);
+	}
+
 /**
  * Returns an array representation of the results
  *

diff --git a/tests/TestCase/Collection/CollectionTest.php b/tests/TestCase/Collection/CollectionTest.php
@@ -676,4 +676,107 @@ function($value, $key) {
 		$this->assertEquals([1 => null, 2 => null, 3 => null], $collection->toArray());
 	}
 
+/**
+ * Tests the nest method with only one level
+ *
+ * @return void
+ */
+	public function testNest() {
+		$items = [
+			['id' => 1, 'parent_id' => null],
+			['id' => 2, 'parent_id' => 1],
+			['id' => 3, 'parent_id' => 1],
+			['id' => 4, 'parent_id' => 1],
+			['id' => 5, 'parent_id' => 6],
+			['id' => 6, 'parent_id' => null],
+			['id' => 7, 'parent_id' => 1],
+			['id' => 8, 'parent_id' => 6],
+			['id' => 9, 'parent_id' => 6],
+			['id' => 10, 'parent_id' => 6]
+		];
+		$collection = (new Collection($items))->nest('id', 'parent_id');
+		$expected = [
+			[
+				'id' => 1,
+				'parent_id' => null,
+				'children' => [
+					['id' => 2, 'parent_id' => 1, 'children' => []],
+					['id' => 3, 'parent_id' => 1, 'children' => []],
+					['id' => 4, 'parent_id' => 1, 'children' => []],
+					['id' => 7, 'parent_id' => 1, 'children' => []]
+				]
+			],
+			[
+				'id' => 6,
+				'parent_id' => null,
+				'children' => [
+					['id' => 5, 'parent_id' => 6, 'children' => []],
+					['id' => 8, 'parent_id' => 6, 'children' => []],
+					['id' => 9, 'parent_id' => 6, 'children' => []],
+					['id' => 10, 'parent_id' => 6, 'children' => []]
+				]
+			]
+		];
+		$this->assertEquals($expected, $collection->toArray());
+	}
+
+/**
+ * Tests the nest method with more than one level
+ *
+ * @return void
+ */
+	public function testNestMultiLevel() {
+		$items = [
+			['id' => 1, 'parent_id' => null],
+			['id' => 2, 'parent_id' => 1],
+			['id' => 3, 'parent_id' => 2],
+			['id' => 4, 'parent_id' => 2],
+			['id' => 5, 'parent_id' => 3],
+			['id' => 6, 'parent_id' => null],
+			['id' => 7, 'parent_id' => 3],
+			['id' => 8, 'parent_id' => 4],
+			['id' => 9, 'parent_id' => 6],
+			['id' => 10, 'parent_id' => 6]
+		];
+		$collection = (new Collection($items))->nest('id', 'parent_id');
+		$expected = [
+			[
+				'id' => 1,
+				'parent_id' => null,
+				'children' => [
+					[
+						'id' => 2,
+						'parent_id' => 1,
+						'children' => [
+							[
+								'id' => 3,
+								'parent_id' => 2,
+								'children' => [
+									['id' => 5, 'parent_id' => 3, 'children' => []],
+									['id' => 7, 'parent_id' => 3, 'children' => []]
+								]
+							],
+							[
+								'id' => 4,
+								'parent_id' => 2,
+								'children' => [
+									['id' => 8, 'parent_id' => 4, 'children' => []]
+								]
+							]
+						]
+					]
+				]
+			],
+			[
+				'id' => 6,
+				'parent_id' => null,
+				'children' => [
+					['id' => 9, 'parent_id' => 6, 'children' => []],
+					['id' => 10, 'parent_id' => 6, 'children' => []]
+				]
+			]
+		];
+		$this->assertEquals($expected, $collection->toArray());
+	}
+
 }