diff --git a/lib/elements/dom-repeat.html b/lib/elements/dom-repeat.html
index 96025ea600..b0365cfa71 100644
--- a/lib/elements/dom-repeat.html
+++ b/lib/elements/dom-repeat.html
@@ -384,7 +384,7 @@
               if (prop == this.as) {
                 this.items[idx] = value;
               }
-              let path = Polymer.Path.translate(this.as, `${JSCompiler_renameProperty('items', this)}.` + idx, prop);
+              let path = Polymer.Path.translate(this.as, `${JSCompiler_renameProperty('items', this)}.${idx}`, prop);
               this.notifyPath(path, value);
             }
           }