don't serialize properties whose original value is object; slight simplification

Author: sorvell

src/instance/attributes.js

@@ -62,24 +62,30 @@
     deserializeValue: function(stringValue, defaultValue) {
       return scope.deserializeValue(stringValue, defaultValue);
     },
-    serializeValue: function(value) {
-      if (typeof value != 'object' && value !== undefined) {
+    serializeValue: function(value, inferredType) {
+      if (inferredType === 'boolean') {
+        return value ? '' : undefined;
+      } else if (inferredType !== 'object' && typeof value !== 'object' &&
+          value !== undefined) {
         return value;
       }
     },
     propertyToAttribute: function(name) {
       if (Object.keys(this[PUBLISHED]).indexOf(name) >= 0) {
-        var serializedValue = this.serializeValue(this[name]);
+        var inferredType = typeof this.__proto__[name];
+        var serializedValue = this.serializeValue(this[name], inferredType);
         // boolean properties must reflect as boolean attributes
-        if (typeof this.__proto__[name] === 'boolean') {
-          if (serializedValue) {
-            this.setAttribute(name, '');
-          } else {
-            this.removeAttribute(name);
-          }
-        } else if (serializedValue !== undefined) {
+        if (serializedValue !== undefined) {
           this.setAttribute(name, serializedValue);
+        // TODO(sorvell): we should remove attr for all properties 
+        // that have undefined serialization; however, we will need to 
+        // refine the attr reflection system to achieve this; pica, for example,
+        // relies on having inferredType object properties not removed as 
+        // attrs.
+        } else if (inferredType === 'boolean') {
+          this.removeAttribute(name);
         }
+        
       }
     }
   };

test/html/prop-attr-reflection.html

@@ -11,7 +11,10 @@
     <x-foo></x-foo>
     <polymer-element name="x-foo" attributes="foo baz">
       <script>
-        Polymer('x-foo');
+        Polymer('x-foo', {
+          foo: '',
+          baz: ''
+        });
       </script>
     </polymer-element>
 
@@ -69,12 +72,12 @@
             Platform.endOfMicrotask(function() {
               assert.equal(xbar.foo, xbar.getAttribute('foo'), 'inherited published property is reflected');
               assert.equal(String(xbar.zot), xbar.getAttribute('zot'), 'attribute reflects property as number');
-              assert.equal('', xbar.getAttribute('zim'), 'attribute reflects true valued boolean property as having attribute');
+              assert.equal(xbar.getAttribute('zim'), '', 'attribute reflects true valued boolean property as having attribute');
               assert.equal(xbar.str, xbar.getAttribute('str'), 'attribute reflects property as published string');
               assert.isFalse(xbar.hasAttribute('obj'), 'attribute does not reflect object property');
+              xbar.setAttribute('zim', 'false');
               xbar.setAttribute('foo', 'foo!!');
               xbar.setAttribute('zot', 54);
-              xbar.setAttribute('zim', 'false');
               xbar.setAttribute('str', 'str!!');
               xbar.setAttribute('obj', "{'hello': 'world'}");
               assert.equal(xbar.foo, xbar.getAttribute('foo'), 'property reflects attribute as string');
@@ -86,7 +89,13 @@
               Platform.flush();
               Platform.endOfMicrotask(function() {
                 assert.isFalse(xbar.hasAttribute('zim'), 'attribute reflects false valued boolean property as NOT having attribute');
-                done();
+                var objAttr = xbar.getAttribute('obj');
+                xbar.obj = 'hi';
+                Platform.endOfMicrotask(function() {
+                  assert.equal(xbar.getAttribute('obj'), objAttr, 'do not reflect property with default type of object');
+                  //assert.isFalse(xbar.hasAttribute('obj'), 'property with default type of object does not serialize');
+                  done();
+                });
               });
             });  
           });