feat(NgTemplateOutlet): add context to NgTemplateOutlet

Closes angular#9042

modules/@angular/common/src/directives/ng_template_outlet.ts

@@ -1,30 +1,53 @@
-import {Directive, Input, TemplateRef, ViewContainerRef, ViewRef} from '@angular/core';
-
+import {Directive, Input, TemplateRef, ViewContainerRef, EmbeddedViewRef} from '@angular/core';
 import {isPresent} from '../facade/lang';
 
 
 /**
  * Creates and inserts an embedded view based on a prepared `TemplateRef`.
+ * You can attach a context object to the `EmbeddedViewRef` by setting `[ngOutletContext]`.
+ * `[ngOutletContext]` should be an object, the object's keys will be the local template variables
+ * available within the `TemplateRef`.
+ *
+ * Note: using the key `$implicit` in the context object will set it's value as default.
  *
  * ### Syntax
- * - `<template [ngTemplateOutlet]="templateRefExpression"></template>`
+ * - `<template [ngTemplateOutlet]="templateRefExpression" [ngOutletContext]="objectExpression"></template>`
  *
  * @experimental
  */
 @Directive({selector: '[ngTemplateOutlet]'})
 export class NgTemplateOutlet {
-  private _insertedViewRef: ViewRef;
+  private _viewRef: EmbeddedViewRef<any>;
+  private _context: Object;
+  private _templateRef: TemplateRef<any>;
 
   constructor(private _viewContainerRef: ViewContainerRef) {}
 
+  @Input()
+  set ngOutletContext(context: Object) {
+    if (this._context !== context) {
+      this._context = context;
+      if (isPresent(this._viewRef)) {
+        this.createView();
+      }
+    }
+  }
+
   @Input()
   set ngTemplateOutlet(templateRef: TemplateRef<Object>) {
-    if (isPresent(this._insertedViewRef)) {
-      this._viewContainerRef.remove(this._viewContainerRef.indexOf(this._insertedViewRef));
+    if (this._templateRef !== templateRef) {
+      this._templateRef = templateRef;
+      this.createView();
+    }
+  }
+
+  private createView() {
+    if (isPresent(this._viewRef)) {
+      this._viewContainerRef.remove(this._viewContainerRef.indexOf(this._viewRef));
     }
 
-    if (isPresent(templateRef)) {
-      this._insertedViewRef = this._viewContainerRef.createEmbeddedView(templateRef);
+    if (isPresent(this._templateRef)) {
+      this._viewRef = this._viewContainerRef.createEmbeddedView(this._templateRef, this._context);
     }
   }
 }

modules/@angular/common/test/directives/ng_template_outlet_spec.ts

@@ -95,6 +95,91 @@ export function main() {
                  });
            }));
 
+    it('should display template if context is null',
+        inject([TestComponentBuilder, AsyncTestCompleter], (tcb: TestComponentBuilder, async) => {
+          var template = `<tpl-refs #refs="tplRefs"><template>foo</template></tpl-refs><template [ngTemplateOutlet]="currentTplRef" [ngOutletContext]="null"></template>`;
+          tcb.overrideTemplate(TestComponent, template)
+            .createAsync(TestComponent)
+            .then((fixture) => {
+
+              fixture.detectChanges();
+              expect(fixture.nativeElement).toHaveText('');
+
+              var refs = fixture.debugElement.children[0].references['refs'];
+
+              fixture.componentInstance.currentTplRef = refs.tplRefs.first;
+              fixture.detectChanges();
+              expect(fixture.nativeElement).toHaveText('foo');
+
+              async.done();
+            });
+        }));
+
+    it('should reflect initial context and changes',
+      inject([TestComponentBuilder, AsyncTestCompleter], (tcb: TestComponentBuilder, async) => {
+        var template =`<tpl-refs #refs="tplRefs"><template let-foo="foo"><span>{{foo}}</span></template></tpl-refs><template [ngTemplateOutlet]="currentTplRef" [ngOutletContext]="context"></template>`;
+        tcb.overrideTemplate(TestComponent, template)
+          .createAsync(TestComponent)
+          .then((fixture) => {
+            fixture.detectChanges();
+
+            var refs = fixture.debugElement.children[0].references['refs'];
+            fixture.componentInstance.currentTplRef = refs.tplRefs.first;
+
+            fixture.detectChanges();
+            expect(fixture.debugElement.nativeElement).toHaveText('bar');
+
+            fixture.componentInstance.context.foo = 'alter-bar';
+
+            fixture.detectChanges();
+            expect(fixture.debugElement.nativeElement).toHaveText('alter-bar');
+
+            async.done();
+          });
+      }));
+
+    it('should reflect user defined $implicit property in the context',
+      inject([TestComponentBuilder, AsyncTestCompleter], (tcb: TestComponentBuilder, async) => {
+        var template =`<tpl-refs #refs="tplRefs"><template let-ctx><span>{{ctx.foo}}</span></template></tpl-refs><template [ngTemplateOutlet]="currentTplRef" [ngOutletContext]="context"></template>`;
+        tcb.overrideTemplate(TestComponent, template)
+          .createAsync(TestComponent)
+          .then((fixture) => {
+            fixture.detectChanges();
+
+            var refs = fixture.debugElement.children[0].references['refs'];
+            fixture.componentInstance.currentTplRef = refs.tplRefs.first;
+
+            fixture.componentInstance.context = { $implicit: fixture.componentInstance.context };
+            fixture.detectChanges();
+            expect(fixture.debugElement.nativeElement).toHaveText('bar');
+
+            async.done();
+          });
+      }));
+
+    it('should reflect context re-binding',
+      inject([TestComponentBuilder, AsyncTestCompleter], (tcb: TestComponentBuilder, async) => {
+        var template =`<tpl-refs #refs="tplRefs"><template let-shawshank="shawshank"><span>{{shawshank}}</span></template></tpl-refs><template [ngTemplateOutlet]="currentTplRef" [ngOutletContext]="context"></template>`;
+        tcb.overrideTemplate(TestComponent, template)
+          .createAsync(TestComponent)
+          .then((fixture) => {
+            fixture.detectChanges();
+
+            var refs = fixture.debugElement.children[0].references['refs'];
+            fixture.componentInstance.currentTplRef = refs.tplRefs.first;
+            fixture.componentInstance.context = { shawshank: 'brooks' };
+
+            fixture.detectChanges();
+            expect(fixture.debugElement.nativeElement).toHaveText('brooks');
+
+            fixture.componentInstance.context = { shawshank: 'was here' };
+
+            fixture.detectChanges();
+            expect(fixture.debugElement.nativeElement).toHaveText('was here');
+
+            async.done();
+          });
+      }));
   });
 }
 
@@ -107,4 +192,5 @@ class CaptureTplRefs {
 @Component({selector: 'test-cmp', directives: [NgTemplateOutlet, CaptureTplRefs], template: ''})
 class TestComponent {
   currentTplRef: TemplateRef<any>;
+  context: any = { foo: 'bar' };
 }

tools/public_api_guard/public_api_spec.ts

@@ -988,6 +988,7 @@ const COMMON = [
   'NgSwitchDefault.constructor(viewContainer:ViewContainerRef, templateRef:TemplateRef<Object>, sswitch:NgSwitch)',
   'NgTemplateOutlet',
   'NgTemplateOutlet.constructor(_viewContainerRef:ViewContainerRef)',
+  'NgTemplateOutlet.ngOutletContext=(context:Object)',
   'NgTemplateOutlet.ngTemplateOutlet=(templateRef:TemplateRef<Object>)',
   'PathLocationStrategy',
   'PathLocationStrategy.back():void',