diff --git a/docs/sync.js b/docs/sync.js
index 770d8583..d2ae2327 100644
--- a/docs/sync.js
+++ b/docs/sync.js
@@ -168,7 +168,7 @@ class User {
     /**
      * Create an admin user for the given authentication server with an existing token
      * @param {string} adminToken - existing admin token
-     * @param {string} [server] - authentication server
+     * @param {string} server - authentication server
      * @return {User} - admin user populated with the given token and server
      */
     static adminUser(adminToken, server) {}
diff --git a/lib/user-methods.js b/lib/user-methods.js
index 98977b6c..7a11fd38 100644
--- a/lib/user-methods.js
+++ b/lib/user-methods.js
@@ -61,6 +61,10 @@ function print_error() {
 }
 
 function refreshAccessToken(user, localRealmPath, realmUrl) {
+    if (!user.server) {
+        throw new Error("Server for user must be specified");
+    }
+
     let parsedRealmUrl = url_parse(realmUrl);
     const url = auth_url(user.server);
     const options = {
@@ -157,12 +161,8 @@ module.exports = {
         },
 
         adminUser(token, server) {
-            checkTypes(arguments, ['string']);
-            const uuid = 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function (c) {
-                var r = Math.random() * 16 | 0, v = c == 'x' ? r : (r & 0x3 | 0x8);
-                return v.toString(16);
-            });
-            return this.createUser(server || '', uuid, token, true);
+            checkTypes(arguments, ['string', 'string']);
+            return this._adminUser(server, token);
         },
 
         register(server, username, password, callback) {
diff --git a/src/js_sync.hpp b/src/js_sync.hpp
index 20218dcb..bd081b7e 100644
--- a/src/js_sync.hpp
+++ b/src/js_sync.hpp
@@ -71,9 +71,11 @@ public:
     };
 
     static void create_user(ContextType, FunctionType, ObjectType, size_t, const ValueType[], ReturnValue &);
+    static void admin_user(ContextType, FunctionType, ObjectType, size_t, const ValueType[], ReturnValue &);
 
     MethodMap<T> const static_methods = {
-        {"createUser", wrap<create_user>}
+        {"createUser", wrap<create_user>},
+        {"_adminUser", wrap<admin_user>}
     };
 
     /*static void current_user(ContextType ctx, ObjectType object, ReturnValue &return_value);*/
@@ -134,6 +136,16 @@ void UserClass<T>::create_user(ContextType ctx, FunctionType, ObjectType this_ob
     return_value.set(create_object<T, UserClass<T>>(ctx, user));
 }
 
+template<typename T>
+void UserClass<T>::admin_user(ContextType ctx, FunctionType, ObjectType this_object, size_t argc, const ValueType arguments[], ReturnValue &return_value) {
+    validate_argument_count(argc, 2, 2);
+    SharedUser *user = new SharedUser(SyncManager::shared().get_admin_token_user(
+        Value::validated_to_string(ctx, arguments[0], "authServerUrl"),
+        Value::validated_to_string(ctx, arguments[1], "refreshToken")
+    ));
+    return_value.set(create_object<T, UserClass<T>>(ctx, user));
+}
+
 template<typename T>
 void UserClass<T>::all_users(ContextType ctx, ObjectType object, ReturnValue &return_value) {
     auto users = Object::create_empty(ctx);
diff --git a/tests/js/admin-user-helper.js b/tests/js/admin-user-helper.js
index a9d1f18b..0bd90141 100644
--- a/tests/js/admin-user-helper.js
+++ b/tests/js/admin-user-helper.js
@@ -23,25 +23,26 @@ function random(min, max) {
     return Math.floor(Math.random() * (max - min + 1)) + min;
 }
 
-let newAdminName = 'admin' + random(1, 100000);
-let password = '123';
-
+const newAdminName = 'admin' + random(1, 100000);
+const password = '123';
 exports.createAdminUser = function () {
+    let nonTokenUser, userIdentity, admin_token_user
     return new Promise((resolve, reject) => {
         Realm.Sync.User.register('http://localhost:9080', newAdminName, password, (error, user) => {
             if (error) {
                 reject(error);
                 return;
             }
-            let userIdentity = user.identity;
+            nonTokenUser = user
+            userIdentity = user.identity;
             user.logout();
 
-            let admin_token_user = Realm.Sync.User.adminUser(getAdminToken());
+            admin_token_user = Realm.Sync.User.adminUser(getAdminToken(), 'http://localhost:9080');
 
             const config = {
                 sync: {
                     user: admin_token_user,
-                    url: `realm://localhost:9080/__admin`,
+                    url: 'realm://localhost:9080/__admin',
                     error: err => {
                         reject(new Error('Error opening __admin realm error:' + err.user  + ' url:' + err.url + ' state:' + err.state));
                     }
@@ -74,7 +75,7 @@ exports.createAdminUser = function () {
                     }
 
                     let isAdmin = newAdminUser.isAdmin;
-                    user.logout();
+                    nonTokenUser.logout();
                     if (!isAdmin) {
                         setTimeout(waitForServerToUpdateAdminUser, 500);
                         return;
diff --git a/tests/js/encryption-tests.js b/tests/js/encryption-tests.js
index f5d3974b..8b3c6b94 100644
--- a/tests/js/encryption-tests.js
+++ b/tests/js/encryption-tests.js
@@ -76,7 +76,7 @@ if (Realm.Sync) {
         new Realm({
             encryptionKey: new Int8Array(64),
             sync: {
-                user: Realm.Sync.User.adminUser('fake-token'),
+                user: Realm.Sync.User.adminUser('fake-token', 'http://fake-server'),
                 url: 'realm://fake-server'
             }
         });