Using visibility fallback for browsers that do not support getters/setters

lib/class.js

@@ -788,6 +788,8 @@ function attachPropInit( prototype, properties, members )
             this, class_instance[ this.__iid ], properties[ 'public' ]
         );
 
+        class_instance[ this.__iid ] = inst_props;
+
         propobj.setup( this, inst_props, properties, members );
     });
 }

lib/propobj.js

@@ -22,7 +22,12 @@
  * @package core
  */
 
-var util = require( './util' );
+var util = require( './util' ),
+
+    // whether or not we support defining properties through
+    // Object.defineProperty()
+    defprop = ( Object.defineProperty !== undefined ) ? true : false;
+;
 
 
 exports.setup = function( base, dest, properties, members )
@@ -81,6 +86,11 @@ exports.createPropProxy = function( base, dest, props )
 {
     var hasOwn = Object.prototype.hasOwnProperty;
 
+    if ( !defprop )
+    {
+        return base;
+    }
+
     for ( prop in props )
     {
         if ( !( hasOwn.call( props, prop ) ) )
@@ -114,3 +124,17 @@ exports.createPropProxy = function( base, dest, props )
     return dest;
 };
 
+
+/**
+ * Returns whether property proxying is supported
+ *
+ * Proxying is done via getters and setters. If the JS engine doesn't support
+ * them (pre-ES5), then the proxy will not work.
+ *
+ * @return  {boolean}  true if supported, otherwise false
+ */
+exports.supportsPropProxy = function()
+{
+    return defprop;
+};
+

test/test-class-visibility.js

@@ -25,6 +25,7 @@
 var common  = require( './common' ),
     assert  = require( 'assert' ),
     Class   = common.require( 'class' ),
+    propobj = common.require( 'propobj' ),
 
     pub  = 'foo',
     prot = 'bar',
@@ -145,6 +146,13 @@ var common = require( './common' ),
 
 ( function testProtectedAndPrivateMembersAreNotAccessibleExternally()
 {
+    // browsers that do not support the property proxy will not support
+    // encapsulating properties
+    if ( !( propobj.supportsPropProxy() ) )
+    {
+        return;
+    }
+
     assert.equal(
         foo.peeps,
         undefined,