diff --git a/lib/persistence.sync.js b/lib/persistence.sync.js
index b063a3a..bf9fc4b 100644
--- a/lib/persistence.sync.js
+++ b/lib/persistence.sync.js
@@ -288,7 +288,7 @@ persistence.sync.postJSON = function(uri, data, callback) {
               { name: 'uri', optional: true, check: argspec.hasType('string'), defaultValue: this.meta.syncUri },
               { name: 'conflictCallback', check: argspec.isCallback() },
               { name: 'callback', check: argspec.isCallback() },
-              { name: 'errorCallback', optional: true, check: argspec.isCallback() },
+              { name: 'errorCallback', optional: true, check: argspec.isCallback() }
             ]);
           synchronize(args.session, args.uri, this, args.conflictCallback, args.callback, args.errorCallback);
         };
diff --git a/persistence.extern.js b/persistence.extern.js
new file mode 100644
index 0000000..ab65c4e
--- /dev/null
+++ b/persistence.extern.js
@@ -0,0 +1,123 @@
+// This file is for Google Closure Compiler to prevent renaming third-party API
+
+var persistence = {};
+
+/** @type {boolean} */
+persistence.debug;
+
+persistence.flush = function(tx, callback){};
+
+persistence.define = function(entityName, fields){};
+
+persistence.schemaSync = function(tx, callback, emulate){};
+
+persistence.migrate = function(){};
+
+/** @type {object} */
+persistence.migrations;
+
+persistence.migrations.init = function(){};
+
+/** @type {object} */
+persistence.store;
+
+/** @type {object} */
+persistence.store.sql;
+
+/** @type {object} */
+persistence.store.websql;
+
+persistence.store.websql.config = function(persistence, dbname, description, size){};
+
+/** @type {object} */
+persistence.store.titanium;
+
+persistence.store.titanium.config = function(persistence, dbname, description, size){};
+
+
+function QueryCollection(){}
+
+QueryCollection.prototype.oldAddEventListener = function(eventType, fn){};
+
+QueryCollection.prototype.setupSubscriptions = function(){};
+
+QueryCollection.prototype.teardownSubscriptions = function(){};
+
+QueryCollection.prototype.addEventListener = function(eventType, fn){};
+
+QueryCollection.prototype.persistQueries = function(){};
+
+QueryCollection.prototype.init = function (session, entityName, constructor){};
+
+QueryCollection.prototype.toUniqueString = function(){};
+
+QueryCollection.prototype.clone = function (cloneSubscribers){};
+
+QueryCollection.prototype.filter = function (property, operator, value){};
+
+QueryCollection.prototype.or = function (filter){};
+
+QueryCollection.prototype.and = function (filter){};
+
+QueryCollection.prototype.order = function (property, ascending){};
+
+QueryCollection.prototype.limit = function(n){};
+
+QueryCollection.prototype.skip = function(n){};
+
+QueryCollection.prototype.reverse = function(){};
+
+QueryCollection.prototype.prefetch = function (rel){};
+
+QueryCollection.prototype.selectJSON = function(tx, props, callback){};
+
+QueryCollection.prototype.add = function(obj){};
+
+QueryCollection.prototype.addAll = function(objs){};
+
+QueryCollection.prototype.remove = function(obj){};
+
+QueryCollection.prototype.each = function(tx, eachFn){};
+
+QueryCollection.prototype.forEach = function(tx, eachFn){};
+
+QueryCollection.prototype.one = function(tx, oneFn){};
+
+
+function LocalQueryCollection(){}
+
+LocalQueryCollection.prototype.count = function(tx, callback){};
+
+LocalQueryCollection.prototype.destroyAll = function(callback){};
+
+LocalQueryCollection.prototype.list = function(tx, callback){};
+
+LocalQueryCollection.prototype.count = function(tx, callback){};
+
+LocalQueryCollection.prototype.remove = function(obj){};
+
+LocalQueryCollection.prototype.addAll = function(objs){};
+
+LocalQueryCollection.prototype.add = function(obj){};
+
+LocalQueryCollection.prototype.clone = function(){};
+
+
+function ManyToManyDbQueryCollection(session, entityName){}
+
+ManyToManyDbQueryCollection.prototype.initManyToMany = function(obj, coll){};
+
+ManyToManyDbQueryCollection.prototype.add = function(obj){};
+
+ManyToManyDbQueryCollection.prototype.addAll = function(objs){};
+
+ManyToManyDbQueryCollection.prototype.clone = function(){};
+
+ManyToManyDbQueryCollection.prototype.remove = function(obj){};
+
+
+function AllDbQueryCollection(session, entityName){}
+
+AllDbQueryCollection.prototype.add = function(obj){};
+
+AllDbQueryCollection.prototype.remove = function(obj){};