Double negate so it also takes care of null

Author: flovilmart

src/ParseServer.js

@@ -181,7 +181,7 @@ class ParseServer {
     // We pass the options and the base class for the adatper,
     // Note that passing an instance would work too
     const pushController = new PushController();
-    const hasPushSupport = (pushAdapter && push) !== undefined;
+    const hasPushSupport = !!(pushAdapter && push);
     const hasPushScheduledSupport = hasPushSupport && (scheduledPush === true);
 
     const {