ZetaGlobalSsp Bid Adapter : cleanup object (#11049)

* ZetaGlobalSsp adapter: cleanup object

* Update zeta_global_sspBidAdapter.js

---------

Co-authored-by: Surovenko Alexey <surovenko.alexey@gmail.com>
Co-authored-by: Alexey Surovenko <ASurovenko@vdhk6ddf9m.home>
Co-authored-by: Chris Huie <phoenixtechnerd@gmail.com>

modules/zeta_global_sspBidAdapter.js

@@ -178,7 +178,7 @@ export const spec = {
     return {
       method: 'POST',
       url: url,
-      data: JSON.stringify(payload),
+      data: JSON.stringify(clearEmpties(payload)),
     };
   },
 
@@ -373,4 +373,17 @@ function provideMediaType(zetaBid, bid, bidRequest) {
   }
 }
 
+function clearEmpties(o) {
+  for (let k in o) {
+    if (!o[k] || typeof o[k] !== 'object') {
+      continue;
+    }
+    clearEmpties(o[k]);
+    if (Object.keys(o[k]).length === 0) {
+      delete o[k];
+    }
+  }
+  return o;
+}
+
 registerBidder(spec);