Allow snapshot and op to be a non-object

Author: gkubisa

lib/ot.js

@@ -102,7 +102,7 @@ exports.apply = function(snapshot, op) {
 function applyOpEdit(snapshot, edit) {
   if (!snapshot.type) return {code: 4015, message: 'Document does not exist'};
 
-  if (typeof edit !== 'object') return {code: 5004, message: 'Missing op'};
+  if (edit == null) return {code: 5004, message: 'Missing op'};
   var type = types[snapshot.type];
   if (!type) return {code: 4008, message: 'Unknown type'};