@angular/cdk/fesm2022/_recycle-view-repeater-strategy-chunk.mjs

Angular Material Component Development Kit

import { isObservable, of } from 'rxjs';
import { DataSource } from './_data-source-chunk.mjs';
import { InjectionToken } from '@angular/core';

class ArrayDataSource extends DataSource {
  _data;
  constructor(_data) {
    super();
    this._data = _data;
  }
  connect() {
    return isObservable(this._data) ? this._data : of(this._data);
  }
  disconnect() {}
}

var _ViewRepeaterOperation;
(function (_ViewRepeaterOperation) {
  _ViewRepeaterOperation[_ViewRepeaterOperation["REPLACED"] = 0] = "REPLACED";
  _ViewRepeaterOperation[_ViewRepeaterOperation["INSERTED"] = 1] = "INSERTED";
  _ViewRepeaterOperation[_ViewRepeaterOperation["MOVED"] = 2] = "MOVED";
  _ViewRepeaterOperation[_ViewRepeaterOperation["REMOVED"] = 3] = "REMOVED";
})(_ViewRepeaterOperation || (_ViewRepeaterOperation = {}));
const _VIEW_REPEATER_STRATEGY = new InjectionToken('_ViewRepeater');

class _RecycleViewRepeaterStrategy {
  viewCacheSize = 20;
  _viewCache = [];
  applyChanges(changes, viewContainerRef, itemContextFactory, itemValueResolver, itemViewChanged) {
    changes.forEachOperation((record, adjustedPreviousIndex, currentIndex) => {
      let view;
      let operation;
      if (record.previousIndex == null) {
        const viewArgsFactory = () => itemContextFactory(record, adjustedPreviousIndex, currentIndex);
        view = this._insertView(viewArgsFactory, currentIndex, viewContainerRef, itemValueResolver(record));
        operation = view ? _ViewRepeaterOperation.INSERTED : _ViewRepeaterOperation.REPLACED;
      } else if (currentIndex == null) {
        this._detachAndCacheView(adjustedPreviousIndex, viewContainerRef);
        operation = _ViewRepeaterOperation.REMOVED;
      } else {
        view = this._moveView(adjustedPreviousIndex, currentIndex, viewContainerRef, itemValueResolver(record));
        operation = _ViewRepeaterOperation.MOVED;
      }
      if (itemViewChanged) {
        itemViewChanged({
          context: view?.context,
          operation,
          record
        });
      }
    });
  }
  detach() {
    for (const view of this._viewCache) {
      view.destroy();
    }
    this._viewCache = [];
  }
  _insertView(viewArgsFactory, currentIndex, viewContainerRef, value) {
    const cachedView = this._insertViewFromCache(currentIndex, viewContainerRef);
    if (cachedView) {
      cachedView.context.$implicit = value;
      return undefined;
    }
    const viewArgs = viewArgsFactory();
    return viewContainerRef.createEmbeddedView(viewArgs.templateRef, viewArgs.context, viewArgs.index);
  }
  _detachAndCacheView(index, viewContainerRef) {
    const detachedView = viewContainerRef.detach(index);
    this._maybeCacheView(detachedView, viewContainerRef);
  }
  _moveView(adjustedPreviousIndex, currentIndex, viewContainerRef, value) {
    const view = viewContainerRef.get(adjustedPreviousIndex);
    viewContainerRef.move(view, currentIndex);
    view.context.$implicit = value;
    return view;
  }
  _maybeCacheView(view, viewContainerRef) {
    if (this._viewCache.length < this.viewCacheSize) {
      this._viewCache.push(view);
    } else {
      const index = viewContainerRef.indexOf(view);
      if (index === -1) {
        view.destroy();
      } else {
        viewContainerRef.remove(index);
      }
    }
  }
  _insertViewFromCache(index, viewContainerRef) {
    const cachedView = this._viewCache.pop();
    if (cachedView) {
      viewContainerRef.insert(cachedView, index);
    }
    return cachedView || null;
  }
}

export { ArrayDataSource, _RecycleViewRepeaterStrategy, _VIEW_REPEATER_STRATEGY, _ViewRepeaterOperation };
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