feat: support binding to class.classname

Closes #551

modules/core/src/compiler/pipeline/element_binder_builder.js

@@ -1,4 +1,4 @@
-import {int, isPresent, isBlank, Type, BaseException, stringify} from 'facade/src/lang';
+import {int, isPresent, isBlank, Type, BaseException, StringWrapper, stringify} from 'facade/src/lang';
 import {Element, DOM} from 'facade/src/dom';
 import {ListWrapper, List, MapWrapper, StringMapWrapper} from 'facade/src/collection';
 
@@ -16,6 +16,26 @@ import {CompileStep} from './compile_step';
 import {CompileElement} from './compile_element';
 import {CompileControl} from './compile_control';
 
+const CLASS_PREFIX = 'class.';
+var classSettersCache = StringMapWrapper.create();
+
+function classSetterFactory(className:string) {
+  var setterFn = StringMapWrapper.get(classSettersCache, className);
+
+  if (isBlank(setterFn)) {
+    setterFn = function(element:Element, value) {
+      if (value) {
+        DOM.addClass(element, className);
+      } else {
+        DOM.removeClass(element, className);
+      }
+    };
+    StringMapWrapper.set(classSettersCache, className, setterFn);
+  }
+
+  return setterFn;
+}
+
 /**
  * Creates the ElementBinders and adds watches to the
  * ProtoChangeDetector.
@@ -72,8 +92,16 @@ export class ElementBinderBuilder extends CompileStep {
 
   _bindElementProperties(protoView, compileElement) {
     MapWrapper.forEach(compileElement.propertyBindings, (expression, property) => {
-      if (DOM.hasProperty(compileElement.element, property)) {
-        protoView.bindElementProperty(expression.ast, property, reflector.setter(property));
+      var setterFn;
+      
+      if (StringWrapper.startsWith(property, CLASS_PREFIX)) {
+        setterFn = classSetterFactory(StringWrapper.substring(property, CLASS_PREFIX.length));
+      } else if (DOM.hasProperty(compileElement.element, property)) {
+        setterFn = reflector.setter(property);
+      }
+
+      if (isPresent(setterFn)) {
+        protoView.bindElementProperty(expression.ast, property, setterFn);
       }
     });
   }

modules/core/test/compiler/integration_spec.js

@@ -69,6 +69,22 @@ export function main() {
         });
       });
 
+      it('should consume element binding for class attribute', (done) => {
+        compiler.compile(MyComp, el('<div class="foo" [class.bar]="boolProp"></div>')).then((pv) => {
+          createView(pv);
+
+          ctx.boolProp = true;
+          cd.detectChanges();
+          expect(view.nodes[0].className).toEqual('foo ng-binding bar');
+
+          ctx.boolProp = false;
+          cd.detectChanges();
+          expect(view.nodes[0].className).toEqual('foo ng-binding');
+
+          done();
+        });
+      });
+
       it('should support nested components.', (done) => {
         compiler.compile(MyComp, el('<child-cmp></child-cmp>')).then((pv) => {
           createView(pv);
@@ -147,6 +163,7 @@ class MyDir {
 })
 class MyComp {
   ctxProp:string;
+  boolProp:boolean;
   constructor() {
     this.ctxProp = 'initial value';
   }

modules/core/test/compiler/pipeline/element_binder_builder_spec.js

@@ -176,6 +176,27 @@ export function main() {
       expect(view.nodes[0].hidden).toEqual(false);
     });
 
+    it('should bind class with a dot', () => {
+      var propertyBindings = MapWrapper.createFromStringMap({
+        'class.bar': 'prop1',
+      });
+      var pipeline = createPipeline({propertyBindings: propertyBindings});
+      var results = pipeline.process(el('<input class="foo" viewroot prop-binding>'));
+      var pv = results[0].inheritedProtoView;
+
+      expect(pv.elementBinders[0].hasElementPropertyBindings).toBe(true);
+
+      instantiateView(pv);
+
+      evalContext.prop1 = true;
+      changeDetector.detectChanges();
+      expect(view.nodes[0].className).toEqual('foo ng-binding bar');
+
+      evalContext.prop1 = false;
+      changeDetector.detectChanges();
+      expect(view.nodes[0].className).toEqual('foo ng-binding');
+    });
+
     it('should bind events', () => {
       var eventBindings = MapWrapper.createFromStringMap({
         'event1': '1+1'

modules/facade/src/dom.dart

@@ -102,6 +102,9 @@ class DOM {
   static void addClass(Element element, String classname) {
     element.classes.add(classname);
   }
+  static void removeClass(Element element, String classname) {
+      element.classes.remove(classname);
+  }
   static bool hasClass(Element element, String classname) =>
       element.classes.contains(classname);
 

modules/facade/src/dom.es6

@@ -121,6 +121,9 @@ export class DOM {
   static addClass(element:Element, classname:string) {
     element.classList.add(classname);
   }
+  static removeClass(element:Element, classname:string) {
+    element.classList.remove(classname);
+  }
   static hasClass(element:Element, classname:string) {
     return element.classList.contains(classname);
   }

modules/facade/src/lang.dart

@@ -62,6 +62,10 @@ class StringWrapper {
     return s.replaceAll(from, replace);
   }
 
+  static startsWith(String s, String start) {
+    return s.startsWith(start);
+  }
+
   static String substring(String s, int start, [int end]) {
     return s.substring(start, end);
   }

modules/facade/src/lang.es6

@@ -68,6 +68,10 @@ export class StringWrapper {
     return s.replace(from.multiple, replace);
   }
 
+  static startsWith(s:string, start:string) {
+    return s.startsWith(start);
+  }
+
   static substring(s:string, start:int, end:int = undefined) {
     return s.substring(start, end);
   }