Down-integrate from google3.
diff --git a/js/binary/constants.js b/js/binary/constants.js
index 21c5889..5c53a36 100644
--- a/js/binary/constants.js
+++ b/js/binary/constants.js
@@ -174,7 +174,7 @@
 
 /**
  * A comparer function returns true if two protos are equal.
- * @typedef {!function(?jspb.ConstBinaryMessage,
+ * @typedef {function(?jspb.ConstBinaryMessage,
  *                     ?jspb.ConstBinaryMessage):boolean}
  */
 jspb.ComparerFunction;