feat(NgStyle): add new NgStyle directive

gulpfile.js

@@ -439,7 +439,7 @@ gulp.task('!test.unit.js/karma-run', function(done) {
 gulp.task('test.unit.dart', function (done) {
   runSequence(
     'build/tree.dart',
-    '!build/pubget.angular2.dart',
+    //'!build/pubget.angular2.dart',
     '!build/change_detect.dart',
     '!test.unit.dart/karma-server',
     '!test.unit.dart/karma-run',

modules/angular2/src/directives/ng_style.ts

@@ -0,0 +1,36 @@
+import {Directive, onCheck} from 'angular2/annotations';
+import {ElementRef} from 'angular2/core';
+import {PipeRegistry} from 'angular2/src/change_detection/pipes/pipe_registry';
+import {isPresent, print} from 'angular2/src/facade/lang';
+import {Renderer} from 'angular2/src/render/api';
+
+@Directive({selector: '[ng-style]', lifecycle: [onCheck], properties: ['rawStyle: ng-style']})
+export class NgStyle {
+  _pipe;
+  _rawStyle;
+
+  constructor(private _pipeRegistry: PipeRegistry, private _ngEl: ElementRef,
+              private _renderer: Renderer) {}
+
+  set rawStyle(v) {
+    this._rawStyle = v;
+    this._pipe = this._pipeRegistry.get('keyValDiff', this._rawStyle);
+  }
+
+  onCheck() {
+    var diff = this._pipe.transform(this._rawStyle);
+    if (isPresent(diff) && isPresent(diff.wrapped)) {
+      this._applyChanges(diff.wrapped);
+    }
+  }
+
+  private _applyChanges(diff): void {
+    diff.forEachAddedItem((record) => { this._setStyle(record.key, record.currentValue); });
+    diff.forEachChangedItem((record) => { this._setStyle(record.key, record.currentValue); });
+    diff.forEachRemovedItem((record) => { this._setStyle(record.key, null); });
+  }
+
+  private _setStyle(name: string, val: string): void {
+    this._renderer.setElementStyle(this._ngEl, name, val);
+  }
+}

modules/angular2/test/directives/ng_style_spec.ts

@@ -0,0 +1,126 @@
+import {
+  AsyncTestCompleter,
+  beforeEach,
+  beforeEachBindings,
+  ddescribe,
+  xdescribe,
+  describe,
+  el,
+  expect,
+  iit,
+  inject,
+  it,
+  xit,
+} from 'angular2/test_lib';
+
+import {StringMapWrapper} from 'angular2/src/facade/collection';
+
+import {Component, View} from 'angular2/angular2';
+
+import {TestBed} from 'angular2/src/test_lib/test_bed';
+import {DOM} from 'angular2/src/dom/dom_adapter';
+import {NgStyle} from 'angular2/src/directives/ng_style';
+
+export function main() {
+  describe('binding to CSS styles', () => {
+
+    it('should add styles specified in an object literal',
+       inject([TestBed, AsyncTestCompleter], (tb: TestBed, async) => {
+         var template = `<div [ng-style]="{'text-align': 'right'}"></div>`;
+
+         tb.createView(TestComponent, {html: template})
+             .then((view) => {
+               view.detectChanges();
+               expect(DOM.getStyle(view.rootNodes[0], 'text-align')).toEqual('right');
+
+               async.done();
+             });
+       }));
+
+    it('should add and change styles specified in an object expression',
+       inject([TestBed, AsyncTestCompleter], (tb: TestBed, async) => {
+         var template = `<div [ng-style]="expr"></div>`;
+
+         tb.createView(TestComponent, {html: template})
+             .then((view) => {
+               var expr: Map<string, any>;
+
+               view.context.expr = {'text-align': 'right'};
+               view.detectChanges();
+               expect(DOM.getStyle(view.rootNodes[0], 'text-align')).toEqual('right');
+
+               expr = view.context.expr;
+               expr['text-align'] = 'left';
+               view.detectChanges();
+               expect(DOM.getStyle(view.rootNodes[0], 'text-align')).toEqual('left');
+
+               async.done();
+             });
+       }));
+
+    it('should remove styles when deleting a key in an object expression',
+       inject([TestBed, AsyncTestCompleter], (tb: TestBed, async) => {
+         var template = `<div [ng-style]="expr"></div>`;
+
+         tb.createView(TestComponent, {html: template})
+             .then((view) => {
+               view.context.expr = {'text-align': 'right'};
+               view.detectChanges();
+               expect(DOM.getStyle(view.rootNodes[0], 'text-align')).toEqual('right');
+
+               StringMapWrapper.delete(view.context.expr, 'text-align');
+               view.detectChanges();
+               expect(DOM.getStyle(view.rootNodes[0], 'text-align')).toEqual('');
+
+               async.done();
+             });
+       }));
+
+    it('should co-operate with the style attribute',
+       inject([TestBed, AsyncTestCompleter], (tb: TestBed, async) => {
+         var template = `<div style="font-size: 12px" [ng-style]="expr"></div>`;
+
+         tb.createView(TestComponent, {html: template})
+             .then((view) => {
+               view.context.expr = {'text-align': 'right'};
+               view.detectChanges();
+               expect(DOM.getStyle(view.rootNodes[0], 'text-align')).toEqual('right');
+               expect(DOM.getStyle(view.rootNodes[0], 'font-size')).toEqual('12px');
+
+               StringMapWrapper.delete(view.context.expr, 'text-align');
+               view.detectChanges();
+               expect(DOM.getStyle(view.rootNodes[0], 'text-align')).toEqual('');
+               expect(DOM.getStyle(view.rootNodes[0], 'font-size')).toEqual('12px');
+
+               async.done();
+             });
+       }));
+
+    it('should co-operate with the style.[styleName]="expr" special-case in the compiler',
+       inject([TestBed, AsyncTestCompleter], (tb: TestBed, async) => {
+         var template = `<div [style.font-size.px]="12" [ng-style]="expr"></div>`;
+
+         tb.createView(TestComponent, {html: template})
+             .then((view) => {
+               view.context.expr = {'text-align': 'right'};
+               view.detectChanges();
+               expect(DOM.getStyle(view.rootNodes[0], 'text-align')).toEqual('right');
+               expect(DOM.getStyle(view.rootNodes[0], 'font-size')).toEqual('12px');
+
+               StringMapWrapper.delete(view.context.expr, 'text-align');
+               expect(DOM.getStyle(view.rootNodes[0], 'font-size')).toEqual('12px');
+
+               view.detectChanges();
+               expect(DOM.getStyle(view.rootNodes[0], 'text-align')).toEqual('');
+
+               async.done();
+             });
+       }));
+  })
+}
+
+@Component({selector: 'test-cmp'})
+@View({directives: [NgStyle]})
+class TestComponent {
+  expr;
+}