fix nth where step <= offset (#41645)

Co-authored-by: Misha van Tol <misha.vantol@synetic.nl>

Author: mishavantol

src/Illuminate/Collections/Collection.php

@@ -806,8 +806,8 @@ public function nth($step, $offset = 0)
 
         $position = 0;
 
-        foreach ($this->items as $item) {
-            if ($position % $step === $offset) {
+        foreach ($this->slice($offset)->items as $item) {
+            if ($position % $step === 0) {
                 $new[] = $item;
             }
 

src/Illuminate/Collections/LazyCollection.php

@@ -796,8 +796,8 @@ public function nth($step, $offset = 0)
         return new static(function () use ($step, $offset) {
             $position = 0;
 
-            foreach ($this as $item) {
-                if ($position % $step === $offset) {
+            foreach ($this->slice($offset) as $item) {
+                if ($position % $step === 0) {
                     yield $item;
                 }
 

tests/Support/SupportCollectionTest.php

@@ -2956,6 +2956,8 @@ public function testNth($collection)
         $this->assertEquals(['b', 'f'], $data->nth(4, 1)->all());
         $this->assertEquals(['c'], $data->nth(4, 2)->all());
         $this->assertEquals(['d'], $data->nth(4, 3)->all());
+        $this->assertEquals(['c', 'e'], $data->nth(2, 2)->all());
+        $this->assertEquals(['c', 'd', 'e', 'f'], $data->nth(1, 2)->all());
     }
 
     /**