Add has_old helper

Author: natanfelles

boot/helpers.php

@@ -164,6 +164,22 @@ function old(?string $key, bool $escape = true) : mixed
     return $data;
 }
 
+/**
+ * Tells if session has old data.
+ *
+ * @param string|null $key null to check all data or a specific key in the
+ * array simple format
+ *
+ * @see old()
+ *
+ * @return bool
+ */
+function has_old(string $key = null) : bool
+{
+    App::session()->activate();
+    return App::request()->getRedirectData($key) !== null;
+}
+
 /**
  * Renders the AntiCSRF input.
  *

tests/boot/HelpersTest.php

@@ -92,14 +92,7 @@ public function testSession() : void
 
     public function testOld() : void
     {
-        App::session()->activate();
-        App::response()->redirect('/foo', [
-            'user' => [
-                'name' => 'John Doe',
-            ],
-            'xss' => '<script>alert("xss")</script>',
-        ]);
-        App::session()->stop();
+        $this->setOldData();
         self::assertSame('', old('user'));
         self::assertSame('John Doe', old('user[name]'));
         self::assertSame(
@@ -112,6 +105,38 @@ public function testOld() : void
         );
     }
 
+    protected function setOldData() : void
+    {
+        App::session()->activate();
+        App::response()->redirect('/foo', [
+            'user' => [
+                'name' => 'John Doe',
+            ],
+            'xss' => '<script>alert("xss")</script>',
+        ]);
+        App::session()->stop();
+    }
+
+    public function testHasOld() : void
+    {
+        $this->setOldData();
+        self::assertTrue(has_old());
+        self::assertTrue(has_old('user'));
+        self::assertTrue(has_old('user[name]'));
+        self::assertTrue(has_old('xss'));
+        self::assertFalse(has_old('foo'));
+        self::assertFalse(has_old('bar'));
+        self::assertFalse(has_old('bar[bazzz]'));
+    }
+
+    public function testHasOldWithoutRedirectData() : void
+    {
+        self::assertFalse(has_old());
+        self::assertFalse(has_old('user'));
+        self::assertFalse(has_old('user[name]'));
+        self::assertFalse(has_old('bar[bazzz]'));
+    }
+
     public function testRedirect() : void
     {
         self::assertNull(App::response()->getHeader('Location'));