diff --git a/src/dispatcher.js b/src/dispatcher.js
index 9864cb3807..f3ebed8357 100644
--- a/src/dispatcher.js
+++ b/src/dispatcher.js
@@ -16,13 +16,13 @@ limitations under the License.
 
 'use strict';
 
-var flux = require("flux");
+const flux = require("flux");
 
 class MatrixDispatcher extends flux.Dispatcher {
     /**
      * @param {Object} payload Required. The payload to dispatch.
      *        Must contain at least an 'action' key.
-     * @param {boolean} sync Optional. Pass true to dispatch
+     * @param {boolean=} sync Optional. Pass true to dispatch
      *        synchronously. This is useful for anything triggering
      *        an operation that the browser requires user interaction
      *        for.