Add unique parameter for push, fixes #91

README.md

@@ -422,6 +422,10 @@ Add an items to an array.
     DB::collection('users')->where('name', 'John')->push('items', 'boots');
     DB::collection('users')->where('name', 'John')->push('messages', array('from' => 'Jane Doe', 'message' => 'Hi John'));
 
+If you don't want duplicate items, set the third parameter to `true`:
+
+    DB::collection('users')->where('name', 'John')->push('items', 'boots', true);
+
 **Pull**
 
 Remove an item from an array.

src/Jenssegers/Mongodb/Query/Builder.php

@@ -522,15 +522,18 @@ class Builder extends \Illuminate\Database\Query\Builder {
      * @param  mixed   $value
      * @return int
      */
-    public function push($column, $value = null)
+    public function push($column, $value = null, $unique = false)
     {
+        // Use the addToSet operator in case we only want unique items.
+        $operator = $unique ? '$addToSet' : '$push';
+
         if (is_array($column))
         {
-            $query = array('$push' => $column);
+            $query = array($operator => $column);
         }
         else
         {
-            $query = array('$push' => array($column => $value));
+            $query = array($operator => array($column => $value));
         }
 
         return $this->performUpdate($query);

tests/QueryBuilderTest.php

@@ -217,15 +217,22 @@ class QueryBuilderTest extends PHPUnit_Framework_TestCase {
 		$this->assertEquals('tag1', $user['tags'][0]);
 
 		DB::collection('users')->where('_id', $id)->push('tags', 'tag2');
-
 		$user = DB::collection('users')->find($id);
-		$this->assertTrue(is_array($user['tags']));
 		$this->assertEquals(2, count($user['tags']));
 		$this->assertEquals('tag2', $user['tags'][1]);
 
+		// Add duplicate
+		DB::collection('users')->where('_id', $id)->push('tags', 'tag2');
+		$user = DB::collection('users')->find($id);
+		$this->assertEquals(3, count($user['tags']));
+
+		// Add unique
+		DB::collection('users')->where('_id', $id)->push('tags', 'tag1', true);
+		$user = DB::collection('users')->find($id);
+		$this->assertEquals(3, count($user['tags']));
+
 		$message = array('from' => 'Jane', 'body' => 'Hi John');
 		DB::collection('users')->where('_id', $id)->push('messages', $message);
-
 		$user = DB::collection('users')->find($id);
 		$this->assertTrue(is_array($user['messages']));
 		$this->assertEquals($message, $user['messages'][0]);