feat(ivy): support attaching and detaching views from change detection (#22670)

PR Close #22670

packages/core/src/render3/component.ts

@@ -16,7 +16,7 @@ import {queueLifecycleHooks} from './hooks';
 import {CLEAN_PROMISE, _getComponentHostLElementNode, createLView, createTView, directiveCreate, enterView, getDirectiveInstance, getRootView, hostElement, initChangeDetectorIfExisting, leaveView, locateHostElement, scheduleTick, tick} from './instructions';
 import {ComponentDef, ComponentType} from './interfaces/definition';
 import {RElement, RendererFactory3, domRendererFactory3} from './interfaces/renderer';
-import {LViewFlags, RootContext} from './interfaces/view';
+import {LView, LViewFlags, RootContext} from './interfaces/view';
 import {stringify} from './util';
 import {createViewRef} from './view_ref';
 
@@ -74,13 +74,14 @@ export interface CreateComponentOptions {
 export function createComponentRef<T>(
     componentType: ComponentType<T>, opts: CreateComponentOptions): viewEngine_ComponentRef<T> {
   const component = renderComponent(componentType, opts);
-  const hostView = createViewRef(component);
+  const hostView = _getComponentHostLElementNode(component).data as LView;
+  const hostViewRef = createViewRef(hostView, component);
   return {
     location: {nativeElement: getHostElement(component)},
     injector: opts.injector || NULL_INJECTOR,
     instance: component,
-    hostView: hostView,
+    hostView: hostViewRef,
-    changeDetectorRef: hostView,
+    changeDetectorRef: hostViewRef,
     componentType: componentType,
     // TODO: implement destroy and onDestroy
     destroy: () => {},

packages/core/src/render3/di.ts

@@ -25,6 +25,7 @@ import {LInjector} from './interfaces/injector';
 import {LContainerNode, LElementNode, LNode, LNodeFlags, LViewNode} from './interfaces/node';
 import {QueryReadType} from './interfaces/query';
 import {Renderer3} from './interfaces/renderer';
+import {LView} from './interfaces/view';
 import {assertNodeOfPossibleTypes, assertNodeType} from './node_assert';
 import {insertView} from './node_manipulation';
 import {notImplemented, stringify} from './util';
@@ -301,7 +302,7 @@ export function getOrCreateChangeDetectorRef(
     return di.changeDetectorRef = getOrCreateHostChangeDetector(currentNode.view.node);
   } else if ((currentNode.flags & LNodeFlags.TYPE_MASK) === LNodeFlags.Element) {
     // if it's an element node with data, it's a component and context will be set later
-    return di.changeDetectorRef = createViewRef(context);
+    return di.changeDetectorRef = createViewRef(currentNode.data as LView, context);
   }
   return null !;
 }
@@ -313,8 +314,10 @@ function getOrCreateHostChangeDetector(currentNode: LViewNode | LElementNode):
   const hostInjector = hostNode.nodeInjector;
   const existingRef = hostInjector && hostInjector.changeDetectorRef;
 
-  return existingRef ? existingRef :
+  return existingRef ?
-                       createViewRef(hostNode.view.data[hostNode.flags >> LNodeFlags.INDX_SHIFT]);
+      existingRef :
+      createViewRef(
+          hostNode.data as LView, hostNode.view.data[hostNode.flags >> LNodeFlags.INDX_SHIFT]);
 }
 
 /**

packages/core/src/render3/instructions.ts

@@ -210,7 +210,7 @@ export function createLView(
   const newView = {
     parent: currentView,
     id: viewId,  // -1 for component views
-    flags: flags | LViewFlags.CreationMode,
+    flags: flags | LViewFlags.CreationMode | LViewFlags.Attached,
     node: null !,  // until we initialize it in createNode.
     data: [],
     tView: tView,
@@ -1281,14 +1281,19 @@ export function directiveRefresh<T>(directiveIndex: number, elementIndex: number
         assertNotNull(element.data, `Component's host node should have an LView attached.`);
     const hostView = element.data !;
 
-    // Only CheckAlways components or dirty OnPush components should be checked
+    // Only attached CheckAlways components or attached, dirty OnPush components should be checked
-    if (hostView.flags & (LViewFlags.CheckAlways | LViewFlags.Dirty)) {
+    if (viewAttached(hostView) && hostView.flags & (LViewFlags.CheckAlways | LViewFlags.Dirty)) {
       ngDevMode && assertDataInRange(directiveIndex);
       detectChangesInternal(hostView, element, getDirectiveInstance<T>(data[directiveIndex]));
     }
   }
 }
 
+/** Returns a boolean for whether the view is attached */
+function viewAttached(view: LView): boolean {
+  return (view.flags & LViewFlags.Attached) === LViewFlags.Attached;
+}
+
 /**
  * Instruction to distribute projectable nodes among <ng-content> occurrences in a given template.
  * It takes all the selectors from the entire component's template and decides where

packages/core/src/render3/interfaces/view.ts

@@ -183,13 +183,16 @@ export const enum LViewFlags {
    * back into the parent view, `data` will be defined and `creationMode` will be
    * improperly reported as false.
    */
-  CreationMode = 0b001,
+  CreationMode = 0b0001,
 
   /** Whether this view has default change detection strategy (checks always) or onPush */
-  CheckAlways = 0b010,
+  CheckAlways = 0b0010,
 
   /** Whether or not this view is currently dirty (needing check) */
-  Dirty = 0b100
+  Dirty = 0b0100,
+
+  /** Whether or not this view is currently attached to change detection tree. */
+  Attached = 0b1000,
 }
 
 /** Interface necessary to work with view tree traversal */

packages/core/src/render3/view_ref.ts

@@ -7,16 +7,18 @@
  */
 
 import {EmbeddedViewRef as viewEngine_EmbeddedViewRef} from '../linker/view_ref';
+
 import {detectChanges} from './instructions';
 import {ComponentTemplate} from './interfaces/definition';
 import {LViewNode} from './interfaces/node';
+import {LView, LViewFlags} from './interfaces/view';
 import {notImplemented} from './util';
 
 export class ViewRef<T> implements viewEngine_EmbeddedViewRef<T> {
   context: T;
   rootNodes: any[];
 
-  constructor(context: T|null) { this.context = context !; }
+  constructor(private _view: LView, context: T|null, ) { this.context = context !; }
 
   /** @internal */
   _setComponentContext(context: T) { this.context = context; }
@@ -25,12 +27,27 @@ export class ViewRef<T> implements viewEngine_EmbeddedViewRef<T> {
   destroyed: boolean;
   onDestroy(callback: Function) { notImplemented(); }
   markForCheck(): void { notImplemented(); }
-  detach(): void { notImplemented(); }
+
+  /**
+   * Detaches a view from the change detection tree.
+   *
+   * Detached views will not be checked during change detection runs, even if the view
+   * is dirty. This can be used in combination with detectChanges to implement local
+   * change detection checks.
+   */
+  detach(): void { this._view.flags &= ~LViewFlags.Attached; }
+
+  /**
+   * Re-attaches a view to the change detection tree.
+   *
+   * This can be used to re-attach views that were previously detached from the tree
+   * using detach(). Views are attached to the tree by default.
+   */
+  reattach(): void { this._view.flags |= LViewFlags.Attached; }
 
   detectChanges(): void { detectChanges(this.context); }
 
   checkNoChanges(): void { notImplemented(); }
-  reattach(): void { notImplemented(); }
 }
 
 
@@ -41,7 +58,7 @@ export class EmbeddedViewRef<T> extends ViewRef<T> {
   _lViewNode: LViewNode;
 
   constructor(viewNode: LViewNode, template: ComponentTemplate<T>, context: T) {
-    super(context);
+    super(viewNode.data, context);
     this._lViewNode = viewNode;
   }
 }
@@ -52,9 +69,9 @@ export class EmbeddedViewRef<T> extends ViewRef<T> {
  * @param context The context for this view
  * @returns The ViewRef
  */
-export function createViewRef<T>(context: T): ViewRef<T> {
+export function createViewRef<T>(view: LView, context: T): ViewRef<T> {
   // TODO: add detectChanges back in when implementing ChangeDetectorRef.detectChanges
-  return addDestroyable(new ViewRef(context));
+  return addDestroyable(new ViewRef(view, context));
 }
 
 /** Interface for destroy logic. Implemented by addDestroyable. */

packages/core/test/render3/change_detection_spec.ts

@@ -11,7 +11,7 @@ import {withBody} from '@angular/core/testing';
 import {ChangeDetectionStrategy, ChangeDetectorRef, DoCheck, EmbeddedViewRef, TemplateRef, ViewContainerRef} from '../../src/core';
 import {getRenderedText, whenRendered} from '../../src/render3/component';
 import {NgOnChangesFeature, PublicFeature, defineComponent, defineDirective, injectChangeDetectorRef, injectTemplateRef, injectViewContainerRef} from '../../src/render3/index';
-import {bind, container, containerRefreshEnd, containerRefreshStart, detectChanges, directiveRefresh, elementEnd, elementProperty, elementStart, embeddedViewEnd, embeddedViewStart, interpolation1, interpolation2, listener, markDirty, text, textBinding} from '../../src/render3/instructions';
+import {bind, container, containerRefreshEnd, containerRefreshStart, detectChanges, directiveRefresh, elementEnd, elementProperty, elementStart, embeddedViewEnd, embeddedViewStart, interpolation1, interpolation2, listener, markDirty, text, textBinding, tick} from '../../src/render3/instructions';
 
 import {containerEl, renderComponent, requestAnimationFrame, toHtml} from './render_util';
 
@@ -146,21 +146,21 @@ describe('change detection', () => {
     it('should call doCheck even when OnPush components are not dirty', () => {
       const myApp = renderComponent(MyApp);
 
-      detectChanges(myApp);
+      tick(myApp);
       expect(comp.doCheckCount).toEqual(2);
 
-      detectChanges(myApp);
+      tick(myApp);
       expect(comp.doCheckCount).toEqual(3);
     });
 
     it('should skip OnPush components in update mode when they are not dirty', () => {
       const myApp = renderComponent(MyApp);
 
-      detectChanges(myApp);
+      tick(myApp);
       // doCheckCount is 2, but 1 should be rendered since it has not been marked dirty.
       expect(getRenderedText(myApp)).toEqual('1 - Nancy');
 
-      detectChanges(myApp);
+      tick(myApp);
       // doCheckCount is 3, but 1 should be rendered since it has not been marked dirty.
       expect(getRenderedText(myApp)).toEqual('1 - Nancy');
     });
@@ -169,14 +169,14 @@ describe('change detection', () => {
       const myApp = renderComponent(MyApp);
 
       myApp.name = 'Bess';
-      detectChanges(myApp);
+      tick(myApp);
       expect(getRenderedText(myApp)).toEqual('2 - Bess');
 
       myApp.name = 'George';
-      detectChanges(myApp);
+      tick(myApp);
       expect(getRenderedText(myApp)).toEqual('3 - George');
 
-      detectChanges(myApp);
+      tick(myApp);
       expect(getRenderedText(myApp)).toEqual('3 - George');
     });
 
@@ -189,7 +189,7 @@ describe('change detection', () => {
       requestAnimationFrame.flush();
       expect(getRenderedText(myApp)).toEqual('2 - Nancy');
 
-      detectChanges(myApp);
+      tick(myApp);
       expect(getRenderedText(myApp)).toEqual('2 - Nancy');
     });
 
@@ -275,7 +275,7 @@ describe('change detection', () => {
       expect(comp !.doCheckCount).toEqual(1);
       expect(getRenderedText(myButtonApp)).toEqual('1 - 1 - Nancy');
 
-      detectChanges(myButtonApp);
+      tick(myButtonApp);
       expect(parent !.doCheckCount).toEqual(2);
       // parent isn't checked, so child doCheck won't run
       expect(comp !.doCheckCount).toEqual(1);
@@ -577,6 +577,185 @@ describe('change detection', () => {
 
     });
 
+    describe('attach/detach', () => {
+      let comp: DetachedComp;
+
+      class MyApp {
+        constructor(public cdr: ChangeDetectorRef) {}
+
+        static ngComponentDef = defineComponent({
+          type: MyApp,
+          tag: 'my-app',
+          factory: () => new MyApp(injectChangeDetectorRef()),
+          /** <detached-comp></detached-comp> */
+          template: (ctx: MyApp, cm: boolean) => {
+            if (cm) {
+              elementStart(0, DetachedComp);
+              elementEnd();
+            }
+            DetachedComp.ngComponentDef.h(1, 0);
+            directiveRefresh(1, 0);
+          }
+        });
+      }
+
+      class DetachedComp {
+        value = 'one';
+        doCheckCount = 0;
+
+        constructor(public cdr: ChangeDetectorRef) {}
+
+        ngDoCheck() { this.doCheckCount++; }
+
+        static ngComponentDef = defineComponent({
+          type: DetachedComp,
+          tag: 'detached-comp',
+          factory: () => comp = new DetachedComp(injectChangeDetectorRef()),
+          /** {{ value }} */
+          template: (ctx: DetachedComp, cm: boolean) => {
+            if (cm) {
+              text(0);
+            }
+            textBinding(0, bind(ctx.value));
+          }
+        });
+      }
+
+      it('should not check detached components', () => {
+        const app = renderComponent(MyApp);
+        expect(getRenderedText(app)).toEqual('one');
+
+        comp.cdr.detach();
+
+        comp.value = 'two';
+        tick(app);
+        expect(getRenderedText(app)).toEqual('one');
+      });
+
+      it('should check re-attached components', () => {
+        const app = renderComponent(MyApp);
+        expect(getRenderedText(app)).toEqual('one');
+
+        comp.cdr.detach();
+        comp.value = 'two';
+
+        comp.cdr.reattach();
+        tick(app);
+        expect(getRenderedText(app)).toEqual('two');
+      });
+
+      it('should call lifecycle hooks on detached components', () => {
+        const app = renderComponent(MyApp);
+        expect(comp.doCheckCount).toEqual(1);
+
+        comp.cdr.detach();
+
+        tick(app);
+        expect(comp.doCheckCount).toEqual(2);
+      });
+
+      it('should check detached component when detectChanges is called', () => {
+        const app = renderComponent(MyApp);
+        expect(getRenderedText(app)).toEqual('one');
+
+        comp.cdr.detach();
+
+        comp.value = 'two';
+        detectChanges(comp);
+        expect(getRenderedText(app)).toEqual('two');
+      });
+
+      it('should not check detached component when markDirty is called', () => {
+        const app = renderComponent(MyApp);
+        expect(getRenderedText(app)).toEqual('one');
+
+        comp.cdr.detach();
+
+        comp.value = 'two';
+        markDirty(comp);
+        requestAnimationFrame.flush();
+
+        expect(getRenderedText(app)).toEqual('one');
+      });
+
+      it('should detach any child components when parent is detached', () => {
+        const app = renderComponent(MyApp);
+        expect(getRenderedText(app)).toEqual('one');
+
+        app.cdr.detach();
+
+        comp.value = 'two';
+        tick(app);
+        expect(getRenderedText(app)).toEqual('one');
+
+        app.cdr.reattach();
+
+        tick(app);
+        expect(getRenderedText(app)).toEqual('two');
+      });
+
+      it('should detach OnPush components properly', () => {
+        let onPushComp: OnPushComp;
+
+        class OnPushComp {
+          /** @Input() */
+          value: string;
+
+          constructor(public cdr: ChangeDetectorRef) {}
+
+          static ngComponentDef = defineComponent({
+            type: OnPushComp,
+            tag: 'on-push-comp',
+            factory: () => onPushComp = new OnPushComp(injectChangeDetectorRef()),
+            /** {{ value }} */
+            template: (ctx: OnPushComp, cm: boolean) => {
+              if (cm) {
+                text(0);
+              }
+              textBinding(0, bind(ctx.value));
+            },
+            changeDetection: ChangeDetectionStrategy.OnPush,
+            inputs: {value: 'value'}
+          });
+        }
+
+        class OnPushApp {
+          value = 'one';
+
+          static ngComponentDef = defineComponent({
+            type: OnPushApp,
+            tag: 'on-push-app',
+            factory: () => new OnPushApp(),
+            /** <on-push-comp [value]="value"></on-push-comp> */
+            template: (ctx: OnPushApp, cm: boolean) => {
+              if (cm) {
+                elementStart(0, OnPushComp);
+                elementEnd();
+              }
+              elementProperty(0, 'value', bind(ctx.value));
+              OnPushComp.ngComponentDef.h(1, 0);
+              directiveRefresh(1, 0);
+            }
+          });
+        }
+
+        const app = renderComponent(OnPushApp);
+        expect(getRenderedText(app)).toEqual('one');
+
+        onPushComp !.cdr.detach();
+
+        app.value = 'two';
+        tick(app);
+        expect(getRenderedText(app)).toEqual('one');
+
+        onPushComp !.cdr.reattach();
+
+        tick(app);
+        expect(getRenderedText(app)).toEqual('two');
+      });
+
+    });
+
   });
 
 });