fix setAttribute issue in Chrome (see #1066); fix using function as `…

…with` argument (fixes #2285)

spec/defaultBindings/withBehaviors.js

@@ -199,4 +199,29 @@ describe('Binding: With', function() {
         // subscription count is stable
         expect(item.getSubscriptionsCount('change')).toEqual(3);
     });
-});
+
+    it('Should update if given a function', function () {
+        // See knockout/knockout#2285
+        testNode.innerHTML = '<div data-bind="with: getTotal">Total: <div data-bind="text: $data"></div>';
+
+        function ViewModel() {
+            var self = this;
+            self.items = ko.observableArray([{ x: ko.observable(4) }])
+            self.getTotal = function() {
+                var total = 0;
+                ko.utils.arrayForEach(self.items(), function(item) { total += item.x();});
+                return total;
+            }
+        }
+
+        var model = new ViewModel();
+        ko.applyBindings(model, testNode);
+        expect(testNode).toContainText("Total: 4");
+
+        model.items.push({ x: ko.observable(15) });
+        expect(testNode).toContainText("Total: 19");
+
+        model.items()[0].x(10);
+        expect(testNode).toContainText("Total: 25");
+    });
+});

src/binding/defaultBindings/attr.js

@@ -6,20 +6,18 @@ ko.bindingHandlers['attr'] = {
             attrValue = ko.utils.unwrapObservable(attrValue);
 
             // Find the namespace of this attribute, if any.
-            // Defaulting to `null` should be ok, as
-            //
-            //  element.setAttributeNS( null, name, value ) ~ element.setAttribute( name, value )
-            //  element.removetAttributeNS( null, name ) ~ element.removeAttribute( name )
-            //
             var prefixLen = attrName.indexOf(':');
-            var namespace = prefixLen < 0 ? null : element.lookupNamespaceURI( attrName.substr(0, prefixLen) );
+            var namespace = prefixLen > 0 && element.lookupNamespaceURI( attrName.substr(0, prefixLen) );
 
             // To cover cases like "attr: { checked:someProp }", we want to remove the attribute entirely
             // when someProp is a "no value"-like value (strictly null, false, or undefined)
             // (because the absence of the "checked" attr is how to mark an element as not checked, etc.)
             var toRemove = (attrValue === false) || (attrValue === null) || (attrValue === undefined);
-            if (toRemove)
-                element.removeAttributeNS(namespace, attrName);
+            if (toRemove) {
+                namespace ? element.removeAttributeNS(namespace, attrName) : element.removeAttribute(attrName);
+            } else {
+                attrValue = attrValue.toString();
+            }
 
             // In IE <= 7 and IE8 Quirks Mode, you have to use the JavaScript property name instead of the
             // HTML attribute name for certain attributes. IE8 Standards Mode supports the correct behavior,
@@ -32,15 +30,15 @@ ko.bindingHandlers['attr'] = {
                 else
                     element[attrName] = attrValue;
             } else if (!toRemove) {
-                element.setAttributeNS(namespace, attrName, attrValue.toString());
+                namespace ? element.setAttributeNS(namespace, attrName, attrValue) : element.setAttribute(attrName, attrValue);
             }
 
             // Treat "name" specially - although you can think of it as an attribute, it also needs
             // special handling on older versions of IE (https://github.com/SteveSanderson/knockout/pull/333)
             // Deliberately being case-sensitive here because XHTML would regard "Name" as a different thing
             // entirely, and there's no strong reason to allow for such casing in HTML.
             if (attrName === "name") {
-                ko.utils.setElementName(element, toRemove ? "" : attrValue.toString());
+                ko.utils.setElementName(element, toRemove ? "" : attrValue);
             }
         });
     }

src/binding/defaultBindings/ifIfnotWith.js

@@ -8,7 +8,8 @@ function makeWithIfBinding(bindingKey, isWith, isNot) {
             }, null, { disposeWhenNodeIsRemoved: element });
 
             ko.computed(function() {
-                var shouldDisplay = isWith ? !!ko.utils.unwrapObservable(valueAccessor()) : ifCondition(),
+                var rawWithValue = isWith && ko.utils.unwrapObservable(valueAccessor()),
+                    shouldDisplay = isWith ? !!rawWithValue : ifCondition(),
                     isFirstRender = !savedNodes;
 
                 // Save a copy of the inner nodes on the initial update, but only if we have dependencies.
@@ -22,7 +23,7 @@ function makeWithIfBinding(bindingKey, isWith, isNot) {
                     }
                     ko.applyBindingsToDescendants(
                         isWith ?
-                            bindingContext['createChildContext'](valueAccessor) :
+                            bindingContext['createChildContext'](typeof rawWithValue == "function" ? rawWithValue : valueAccessor) :
                             ifCondition.isActive() ?
                                 bindingContext['extend'](function() { ifCondition(); return null; }) :
                                 bindingContext,