fix: add flag to force object (#416)

Author: bshaffer

src/JWT.php

@@ -355,7 +355,7 @@ public static function jsonDecode(string $input)
     public static function jsonEncode(array $input): string
     {
         if (PHP_VERSION_ID >= 50400) {
-            $json = \json_encode($input, \JSON_UNESCAPED_SLASHES);
+            $json = \json_encode($input, \JSON_UNESCAPED_SLASHES|\JSON_FORCE_OBJECT);
         } else {
             // PHP 5.3 only
             $json = \json_encode($input);

tests/JWTTest.php

@@ -321,6 +321,15 @@ public function testRSEncodeDecodeWithPassphrase()
         $this->assertEquals($decoded, $expected);
     }
 
+    public function testDecodesEmptyArrayAsObject()
+    {
+        $key = 'yma6Hq4XQegCVND8ef23OYgxSrC3IKqk';
+        $payload = [];
+        $jwt = JWT::encode($payload, $key, 'HS256');
+        $decoded = JWT::decode($jwt, new Key($key, 'HS256'));
+        $this->assertEquals((object) $payload, $decoded);
+    }
+
     /**
      * @runInSeparateProcess
      * @dataProvider provideEncodeDecode