From 030316ef225eabc31c3ea3f632787ed12d1d6e44 Mon Sep 17 00:00:00 2001
From: Kevin Howald <kevinhowald@google.com>
Date: Wed, 26 Apr 2017 11:07:15 -0400
Subject: [PATCH] pr comments

---
 src/service/action-impl.js | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/src/service/action-impl.js b/src/service/action-impl.js
index 08a4f4b019b6..663f2e706132 100644
--- a/src/service/action-impl.js
+++ b/src/service/action-impl.js
@@ -197,9 +197,9 @@ export class ActionService {
    * @param {!Event} event A `change` event.
    */
   addChangeDetails_(event) {
-    const detail = {};
+    const detail = map();
     const target = event.target;
-    const tagName = event.target.tagName.toLowerCase();
+    const tagName = target.tagName.toLowerCase();
     switch (tagName) {
       case 'input':
         const inputType = target.getAttribute('type');
@@ -216,14 +216,15 @@ export class ActionService {
               detail[field] = String(value);
             }
           });
-          event.detail = detail;
         }
         break;
       case 'select':
-        detail['value'] = target['value'];
-        event.detail = detail;
+        detail.value = target.value;
         break;
     }
+    if (Object.keys(detail).length > 0) {
+      event.detail = detail;
+    }
   }
 
   /**