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MichaelJamesParsonsMichaelJamesParsons
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feat(cdk/collections): extract view repeater strategies from virtualForOf and CDK table.
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-149
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15 files changed

+575
-149
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‎goldens/ts-circular-deps.json

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"src/cdk-experimental/dialog/dialog-config.ts",
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"src/cdk-experimental/dialog/dialog-container.ts"
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],
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[
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"src/cdk/collections/dispose-view-repeater-strategy.ts",
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"src/cdk/collections/index.ts",
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"src/cdk/collections/public-api.ts"
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],
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[
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"src/cdk/collections/index.ts",
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"src/cdk/collections/public-api.ts",
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"src/cdk/collections/recycle-view-repeater-strategy.ts"
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],
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[
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"src/cdk/drag-drop/directives/drag.ts",
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"src/cdk/drag-drop/directives/drop-list.ts"

‎src/cdk/collections/dispose-view-repeater-strategy.ts

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/**
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* @license
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* Copyright Google LLC All Rights Reserved.
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*
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* Use of this source code is governed by an MIT-style license that can be
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* found in the LICENSE file at https://angular.io/license
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*/
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import {
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EmbeddedViewRef,
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IterableChangeRecord,
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IterableChanges,
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ViewContainerRef
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} from '@angular/core';
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import {
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_viewRepeater,
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_ViewRepeaterItemChanged,
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_ViewRepeaterItemContext,
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_ViewRepeaterItemContextFactory,
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_ViewRepeaterItemValueResolver,
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_ViewRepeaterOperation
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} from './view-repeater';
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/**
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* A repeater that destroys views when they are removed from a
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* {@link ViewContainerRef}. When new items are inserted into the container,
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* the repeater will always construct a new embedded view for each item.
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*
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* @template T The type for the embedded view's $implicit property.
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* @template R The type for the item in each IterableDiffer change record.
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* @template C The type for the context passed to each embedded view.
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*/
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export class _disposeViewRepeaterStrategy<T, R, C extends _ViewRepeaterItemContext<T>>
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implements _viewRepeater<T, R, C> {
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applyChanges(changes: IterableChanges<R>,
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viewContainerRef: ViewContainerRef,
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itemContextFactory: _ViewRepeaterItemContextFactory<T, R, C>,
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itemValueResolver: _ViewRepeaterItemValueResolver<T, R>,
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itemViewChanged?: _ViewRepeaterItemChanged<R, C>) {
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changes.forEachOperation(
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(record: IterableChangeRecord<R>,
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adjustedPreviousIndex: number | null,
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currentIndex: number | null) => {
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let view: EmbeddedViewRef<C> | undefined;
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let operation: _ViewRepeaterOperation;
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if (record.previousIndex == null) {
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const insertContext = itemContextFactory(record, adjustedPreviousIndex, currentIndex);
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view = viewContainerRef.createEmbeddedView(
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insertContext.templateRef, insertContext.context, insertContext.index);
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operation = _ViewRepeaterOperation.INSERTED;
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} else if (currentIndex == null) {
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viewContainerRef.remove(adjustedPreviousIndex!);
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operation = _ViewRepeaterOperation.REMOVED;
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} else {
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view = viewContainerRef.get(adjustedPreviousIndex!) as EmbeddedViewRef<C>;
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viewContainerRef.move(view!, currentIndex);
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operation = _ViewRepeaterOperation.MOVED;
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}
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if (itemViewChanged) {
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itemViewChanged({
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context: view?.context,
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operation,
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record,
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});
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}
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});
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}
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detach() {
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}
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}

‎src/cdk/collections/public-api.ts

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export * from './array-data-source';
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export * from './collection-viewer';
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export * from './data-source';
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export * from './dispose-view-repeater-strategy';
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export * from './recycle-view-repeater-strategy';
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export * from './selection-model';
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export {
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UniqueSelectionDispatcher,
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UniqueSelectionDispatcherListener,
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} from './unique-selection-dispatcher';
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export * from './tree-adapter';
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export * from './view-repeater';

‎src/cdk/collections/recycle-view-repeater-strategy.ts

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/**
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* @license
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* Copyright Google LLC All Rights Reserved.
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*
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* Use of this source code is governed by an MIT-style license that can be
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* found in the LICENSE file at https://angular.io/license
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*/
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import {
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EmbeddedViewRef,
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IterableChangeRecord,
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IterableChanges,
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IterableDiffer,
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ViewContainerRef
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} from '@angular/core';
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import {
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_viewRepeater,
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_ViewRepeaterItemChanged,
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_ViewRepeaterItemContext,
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_ViewRepeaterItemContextFactory,
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_ViewRepeaterItemInsertArgs,
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_ViewRepeaterItemValueResolver,
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_ViewRepeaterOperation
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} from './view-repeater';
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/**
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* A repeater that caches views when they are removed from a
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* {@link ViewContainerRef}. When new items are inserted into the container,
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* the repeater will reuse one of the cached views instead of creating a new
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* embedded view. Recycling cached views reduces the quantity of expensive DOM
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* inserts.
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*
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* @template T The type for the embedded view's $implicit property.
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* @template R The type for the item in each IterableDiffer change record.
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* @template C The type for the context passed to each embedded view.
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*/
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export class _recycleViewRepeaterStrategy<T, R, C extends _ViewRepeaterItemContext<T>>
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implements _viewRepeater<T, R, C> {
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differ: IterableDiffer<C>;
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/**
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* The size of the cache used to store unused views.
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* Setting the cache size to `0` will disable caching. Defaults to 20 views.
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*/
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viewCacheSize: number = 20;
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/**
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* View cache that stores embedded view instances that have been previously stamped out,
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* but don't are not currently rendered. The view repeater will reuse these views rather than
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* creating brand new ones.
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*
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* TODO(michaeljamesparsons) Investigate whether using a linked list would improve performance.
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*/
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private _viewCache: EmbeddedViewRef<C>[] = [];
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/** Apply changes to the DOM. */
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applyChanges(changes: IterableChanges<R>,
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viewContainerRef: ViewContainerRef,
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itemContextFactory: _ViewRepeaterItemContextFactory<T, R, C>,
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itemValueResolver: _ViewRepeaterItemValueResolver<T, R>,
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itemViewChanged?: _ViewRepeaterItemChanged<R, C>) {
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// Rearrange the views to put them in the right location.
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changes.forEachOperation((record: IterableChangeRecord<R>,
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adjustedPreviousIndex: number | null,
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currentIndex: number | null) => {
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let view: EmbeddedViewRef<C> | undefined;
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let operation: _ViewRepeaterOperation;
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if (record.previousIndex == null) { // Item added.
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const viewArgsFactory = () => itemContextFactory(
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record, adjustedPreviousIndex, currentIndex);
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view = this._insertView(viewArgsFactory, currentIndex!, viewContainerRef,
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itemValueResolver(record));
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operation = view ? _ViewRepeaterOperation.INSERTED : _ViewRepeaterOperation.REPLACED;
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} else if (currentIndex == null) { // Item removed.
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this._detachAndCacheView(adjustedPreviousIndex!, viewContainerRef);
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operation = _ViewRepeaterOperation.REMOVED;
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} else { // Item moved.
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view = this._moveView(adjustedPreviousIndex!, currentIndex!, viewContainerRef,
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itemValueResolver(record));
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operation = _ViewRepeaterOperation.MOVED;
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}
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if (itemViewChanged) {
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itemViewChanged({
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context: view?.context,
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operation,
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record,
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});
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}
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});
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}
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detach() {
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for (const view of this._viewCache) {
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view.destroy();
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}
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}
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/**
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* Inserts a view for a new item, either from the cache or by creating a new
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* one. Returns `undefined` if the item was inserted into a cached view.
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*/
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private _insertView(viewArgsFactory: () => _ViewRepeaterItemInsertArgs<C>, currentIndex: number,
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viewContainerRef: ViewContainerRef,
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value: T): EmbeddedViewRef<C> | undefined {
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let cachedView = this._insertViewFromCache(currentIndex!, viewContainerRef);
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if (cachedView) {
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cachedView.context.$implicit = value;
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return undefined;
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}
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const viewArgs = viewArgsFactory();
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return viewContainerRef.createEmbeddedView(
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viewArgs.templateRef, viewArgs.context, viewArgs.index);
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}
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/** Detaches the view at the given index and inserts into the view cache. */
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private _detachAndCacheView(index: number, viewContainerRef: ViewContainerRef) {
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const detachedView = this._detachView(index, viewContainerRef);
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this._maybeCacheView(detachedView, viewContainerRef);
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}
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/** Moves view at the previous index to the current index. */
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private _moveView(adjustedPreviousIndex: number, currentIndex: number,
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viewContainerRef: ViewContainerRef, value: T): EmbeddedViewRef<C> {
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const view = viewContainerRef.get(adjustedPreviousIndex!) as
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EmbeddedViewRef<C>;
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viewContainerRef.move(view, currentIndex);
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view.context.$implicit = value;
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return view;
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}
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/**
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* Cache the given detached view. If the cache is full, the view will be
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* destroyed.
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*/
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private _maybeCacheView(view: EmbeddedViewRef<C>, viewContainerRef: ViewContainerRef) {
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if (this._viewCache.length < this.viewCacheSize) {
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this._viewCache.push(view);
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} else {
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const index = viewContainerRef.indexOf(view);
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// The host component could remove views from the container outside of
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// the view repeater. It's unlikely this will occur, but just in case,
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// destroy the view on its own, otherwise destroy it through the
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// container to ensure that all the references are removed.
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if (index === -1) {
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view.destroy();
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} else {
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viewContainerRef.remove(index);
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}
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}
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}
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/** Inserts a recycled view from the cache at the given index. */
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private _insertViewFromCache(index: number,
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viewContainerRef: ViewContainerRef): EmbeddedViewRef<C> | null {
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const cachedView = this._viewCache.pop();
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if (cachedView) {
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viewContainerRef.insert(cachedView, index);
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}
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return cachedView || null;
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}
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/** Detaches the embedded view at the given index. */
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private _detachView(index: number, viewContainerRef: ViewContainerRef): EmbeddedViewRef<C> {
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return viewContainerRef.detach(index) as EmbeddedViewRef<C>;
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}
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}

‎src/cdk/collections/view-repeater.ts

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/**
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* @license
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* Copyright Google LLC All Rights Reserved.
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*
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* Use of this source code is governed by an MIT-style license that can be
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* found in the LICENSE file at https://angular.io/license
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*/
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import {
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InjectionToken,
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IterableChangeRecord,
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IterableChanges,
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TemplateRef,
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ViewContainerRef
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} from '@angular/core';
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/**
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* The context for an embedded view in the repeater's view container.
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*
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* @template T The type for the embedded view's $implicit property.
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*/
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export interface _ViewRepeaterItemContext<T> {
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$implicit?: T;
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}
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/**
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* The arguments needed to construct an embedded view for an item in a view
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* container.
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*
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* @template C The type for the context passed to each embedded view.
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*/
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export interface _ViewRepeaterItemInsertArgs<C> {
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templateRef: TemplateRef<C>;
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context?: C;
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index?: number;
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}
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/**
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* A factory that derives the embedded view context for an item in a view
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* container.
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*
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* @template T The type for the embedded view's $implicit property.
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* @template R The type for the item in each IterableDiffer change record.
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* @template C The type for the context passed to each embedded view.
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*/
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export type _ViewRepeaterItemContextFactory<T, R, C extends _ViewRepeaterItemContext<T>> =
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(record: IterableChangeRecord<R>,
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adjustedPreviousIndex: number | null,
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currentIndex: number | null) => _ViewRepeaterItemInsertArgs<C>;
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/**
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* Extracts the value of an item from an {@link IterableChangeRecord}.
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*
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* @template T The type for the embedded view's $implicit property.
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* @template R The type for the item in each IterableDiffer change record.
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*/
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export type _ViewRepeaterItemValueResolver<T, R> =
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(record: IterableChangeRecord<R>) => T;
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/** Indicates how a view was changed by a {@link _viewRepeater}. */
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export const enum _ViewRepeaterOperation {
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/** The content of an existing view was replaced with another item. */
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REPLACED,
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/** A new view was created with `createEmbeddedView`. */
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INSERTED,
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/** The position of a view changed, but the content remains the same. */
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MOVED,
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/** A view was detached from the view container. */
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REMOVED,
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}
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/**
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* Meta data describing the state of a view after it was updated by a
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* {@link _viewRepeater}.
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*
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* @template R The type for the item in each IterableDiffer change record.
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* @template C The type for the context passed to each embedded view.
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*/
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export interface _ViewRepeaterItemChange<R, C> {
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/** The view's context after it was changed. */
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context?: C;
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/** Indicates how the view was changed. */
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operation: _ViewRepeaterOperation;
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/** The view's corresponding change record. */
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record: IterableChangeRecord<R>;
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}
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/**
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* Type for a callback to be executed after a view has changed.
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*
91+
* @template R The type for the item in each IterableDiffer change record.
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* @template C The type for the context passed to each embedded view.
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*/
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export type _ViewRepeaterItemChanged<R, C> =
95+
(change: _ViewRepeaterItemChange<R, C>) => void;
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/**
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* Describes a strategy for rendering items in a {@link ViewContainerRef}.
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*
100+
* @template T The type for the embedded view's $implicit property.
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* @template R The type for the item in each IterableDiffer change record.
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* @template C The type for the context passed to each embedded view.
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*/
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export interface _viewRepeater<T, R, C extends _ViewRepeaterItemContext<T>> {
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applyChanges(
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changes: IterableChanges<R>,
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viewContainerRef: ViewContainerRef,
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itemContextFactory: _ViewRepeaterItemContextFactory<T, R, C>,
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itemValueResolver: _ViewRepeaterItemValueResolver<T, R>,
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itemViewChanged?: _ViewRepeaterItemChanged<R, C>): void;
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detach(): void;
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}
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/**
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* Injection token for {@link _viewRepeater}.
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*
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* INTERNAL ONLY - not for public consumption.
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* @docs-private
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*/
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export const _VIEW_REPEATER_STRATEGY = new InjectionToken<
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_viewRepeater<unknown, unknown, _ViewRepeaterItemContext<unknown>>>('_ViewRepeater');

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