From bdc63e64fe127a1cdf6d358d6aaf65141b28240b Mon Sep 17 00:00:00 2001
From: samreid <reids@colorado.edu>
Date: Thu, 1 Nov 2018 22:49:40 -0600
Subject: [PATCH] hard-code phetioType in StringProperty, see
 https://github.com/phetsims/axon/issues/116

---
 js/StringProperty.js | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/js/StringProperty.js b/js/StringProperty.js
index cb740fae..24d57156 100644
--- a/js/StringProperty.js
+++ b/js/StringProperty.js
@@ -23,13 +23,14 @@ define( function( require ) {
    */
   function StringProperty( value, options ) {
 
-    options = _.extend( {
-      phetioType: PropertyIO( StringIO )
-    }, options );
+    options = options || {};
 
     assert && assert( !options.valueType, 'valueType is set by StringProperty' );
     options.valueType = 'string';
 
+    assert && assert( !options.hasOwnProperty( 'phetioType' ), 'phetioType is set by StringProperty' );
+    options.phetioType = PropertyIO( StringIO );
+
     Property.call( this, value, options );
   }