import { coerceNumberProperty, coerceElement, coerceBooleanProperty } from '@angular/cdk/coercion'; import * as i0 from '@angular/core'; import { InjectionToken, Directive, forwardRef, Input, Injectable, NgZone, Optional, Inject, ElementRef, Component, ViewEncapsulation, ChangeDetectionStrategy, ChangeDetectorRef, Output, ViewChild, ViewContainerRef, TemplateRef, IterableDiffers, SkipSelf, NgModule } from '@angular/core'; import { Subject, of, Observable, fromEvent, animationFrameScheduler, asapScheduler, Subscription, isObservable } from 'rxjs'; import { distinctUntilChanged, auditTime, filter, takeUntil, startWith, pairwise, switchMap, shareReplay } from 'rxjs/operators'; import * as i1 from '@angular/cdk/platform'; import { Platform, getRtlScrollAxisType, supportsScrollBehavior, PlatformModule } from '@angular/cdk/platform'; import * as i2 from '@angular/common'; import { DOCUMENT } from '@angular/common'; import { Directionality, BidiModule } from '@angular/cdk/bidi'; import { isDataSource, ArrayDataSource, _VIEW_REPEATER_STRATEGY, _RecycleViewRepeaterStrategy } from '@angular/cdk/collections'; /** * @license * Copyright Google LLC All Rights Reserved. * * Use of this source code is governed by an MIT-style license that can be * found in the LICENSE file at https://angular.io/license */ /** The injection token used to specify the virtual scrolling strategy. */ const VIRTUAL_SCROLL_STRATEGY = new InjectionToken('VIRTUAL_SCROLL_STRATEGY'); /** * @license * Copyright Google LLC All Rights Reserved. * * Use of this source code is governed by an MIT-style license that can be * found in the LICENSE file at https://angular.io/license */ /** Virtual scrolling strategy for lists with items of known fixed size. */ class FixedSizeVirtualScrollStrategy { /** * @param itemSize The size of the items in the virtually scrolling list. * @param minBufferPx The minimum amount of buffer (in pixels) before needing to render more * @param maxBufferPx The amount of buffer (in pixels) to render when rendering more. */ constructor(itemSize, minBufferPx, maxBufferPx) { this._scrolledIndexChange = new Subject(); /** @docs-private Implemented as part of VirtualScrollStrategy. */ this.scrolledIndexChange = this._scrolledIndexChange.pipe(distinctUntilChanged()); /** The attached viewport. */ this._viewport = null; this._itemSize = itemSize; this._minBufferPx = minBufferPx; this._maxBufferPx = maxBufferPx; } /** * Attaches this scroll strategy to a viewport. * @param viewport The viewport to attach this strategy to. */ attach(viewport) { this._viewport = viewport; this._updateTotalContentSize(); this._updateRenderedRange(); } /** Detaches this scroll strategy from the currently attached viewport. */ detach() { this._scrolledIndexChange.complete(); this._viewport = null; } /** * Update the item size and buffer size. * @param itemSize The size of the items in the virtually scrolling list. * @param minBufferPx The minimum amount of buffer (in pixels) before needing to render more * @param maxBufferPx The amount of buffer (in pixels) to render when rendering more. */ updateItemAndBufferSize(itemSize, minBufferPx, maxBufferPx) { if (maxBufferPx < minBufferPx && (typeof ngDevMode === 'undefined' || ngDevMode)) { throw Error('CDK virtual scroll: maxBufferPx must be greater than or equal to minBufferPx'); } this._itemSize = itemSize; this._minBufferPx = minBufferPx; this._maxBufferPx = maxBufferPx; this._updateTotalContentSize(); this._updateRenderedRange(); } /** @docs-private Implemented as part of VirtualScrollStrategy. */ onContentScrolled() { this._updateRenderedRange(); } /** @docs-private Implemented as part of VirtualScrollStrategy. */ onDataLengthChanged() { this._updateTotalContentSize(); this._updateRenderedRange(); } /** @docs-private Implemented as part of VirtualScrollStrategy. */ onContentRendered() { } /** @docs-private Implemented as part of VirtualScrollStrategy. */ onRenderedOffsetChanged() { } /** * Scroll to the offset for the given index. * @param index The index of the element to scroll to. * @param behavior The ScrollBehavior to use when scrolling. */ scrollToIndex(index, behavior) { if (this._viewport) { this._viewport.scrollToOffset(index * this._itemSize, behavior); } } /** Update the viewport's total content size. */ _updateTotalContentSize() { if (!this._viewport) { return; } this._viewport.setTotalContentSize(this._viewport.getDataLength() * this._itemSize); } /** Update the viewport's rendered range. */ _updateRenderedRange() { if (!this._viewport) { return; } const renderedRange = this._viewport.getRenderedRange(); const newRange = { start: renderedRange.start, end: renderedRange.end }; const viewportSize = this._viewport.getViewportSize(); const dataLength = this._viewport.getDataLength(); let scrollOffset = this._viewport.measureScrollOffset(); // Prevent NaN as result when dividing by zero. let firstVisibleIndex = (this._itemSize > 0) ? scrollOffset / this._itemSize : 0; // If user scrolls to the bottom of the list and data changes to a smaller list if (newRange.end > dataLength) { // We have to recalculate the first visible index based on new data length and viewport size. const maxVisibleItems = Math.ceil(viewportSize / this._itemSize); const newVisibleIndex = Math.max(0, Math.min(firstVisibleIndex, dataLength - maxVisibleItems)); // If first visible index changed we must update scroll offset to handle start/end buffers // Current range must also be adjusted to cover the new position (bottom of new list). if (firstVisibleIndex != newVisibleIndex) { firstVisibleIndex = newVisibleIndex; scrollOffset = newVisibleIndex * this._itemSize; newRange.start = Math.floor(firstVisibleIndex); } newRange.end = Math.max(0, Math.min(dataLength, newRange.start + maxVisibleItems)); } const startBuffer = scrollOffset - newRange.start * this._itemSize; if (startBuffer < this._minBufferPx && newRange.start != 0) { const expandStart = Math.ceil((this._maxBufferPx - startBuffer) / this._itemSize); newRange.start = Math.max(0, newRange.start - expandStart); newRange.end = Math.min(dataLength, Math.ceil(firstVisibleIndex + (viewportSize + this._minBufferPx) / this._itemSize)); } else { const endBuffer = newRange.end * this._itemSize - (scrollOffset + viewportSize); if (endBuffer < this._minBufferPx && newRange.end != dataLength) { const expandEnd = Math.ceil((this._maxBufferPx - endBuffer) / this._itemSize); if (expandEnd > 0) { newRange.end = Math.min(dataLength, newRange.end + expandEnd); newRange.start = Math.max(0, Math.floor(firstVisibleIndex - this._minBufferPx / this._itemSize)); } } } this._viewport.setRenderedRange(newRange); this._viewport.setRenderedContentOffset(this._itemSize * newRange.start); this._scrolledIndexChange.next(Math.floor(firstVisibleIndex)); } } /** * Provider factory for `FixedSizeVirtualScrollStrategy` that simply extracts the already created * `FixedSizeVirtualScrollStrategy` from the given directive. * @param fixedSizeDir The instance of `CdkFixedSizeVirtualScroll` to extract the * `FixedSizeVirtualScrollStrategy` from. */ function _fixedSizeVirtualScrollStrategyFactory(fixedSizeDir) { return fixedSizeDir._scrollStrategy; } /** A virtual scroll strategy that supports fixed-size items. */ class CdkFixedSizeVirtualScroll { constructor() { this._itemSize = 20; this._minBufferPx = 100; this._maxBufferPx = 200; /** The scroll strategy used by this directive. */ this._scrollStrategy = new FixedSizeVirtualScrollStrategy(this.itemSize, this.minBufferPx, this.maxBufferPx); } /** The size of the items in the list (in pixels). */ get itemSize() { return this._itemSize; } set itemSize(value) { this._itemSize = coerceNumberProperty(value); } /** * The minimum amount of buffer rendered beyond the viewport (in pixels). * If the amount of buffer dips below this number, more items will be rendered. Defaults to 100px. */ get minBufferPx() { return this._minBufferPx; } set minBufferPx(value) { this._minBufferPx = coerceNumberProperty(value); } /** * The number of pixels worth of buffer to render for when rendering new items. Defaults to 200px. */ get maxBufferPx() { return this._maxBufferPx; } set maxBufferPx(value) { this._maxBufferPx = coerceNumberProperty(value); } ngOnChanges() { this._scrollStrategy.updateItemAndBufferSize(this.itemSize, this.minBufferPx, this.maxBufferPx); } } CdkFixedSizeVirtualScroll.decorators = [ { type: Directive, args: [{ selector: 'cdk-virtual-scroll-viewport[itemSize]', providers: [{ provide: VIRTUAL_SCROLL_STRATEGY, useFactory: _fixedSizeVirtualScrollStrategyFactory, deps: [forwardRef(() => CdkFixedSizeVirtualScroll)], }], },] } ]; CdkFixedSizeVirtualScroll.propDecorators = { itemSize: [{ type: Input }], minBufferPx: [{ type: Input }], maxBufferPx: [{ type: Input }] }; /** * @license * Copyright Google LLC All Rights Reserved. * * Use of this source code is governed by an MIT-style license that can be * found in the LICENSE file at https://angular.io/license */ /** Time in ms to throttle the scrolling events by default. */ const DEFAULT_SCROLL_TIME = 20; /** * Service contained all registered Scrollable references and emits an event when any one of the * Scrollable references emit a scrolled event. */ class ScrollDispatcher { constructor(_ngZone, _platform, document) { this._ngZone = _ngZone; this._platform = _platform; /** Subject for notifying that a registered scrollable reference element has been scrolled. */ this._scrolled = new Subject(); /** Keeps track of the global `scroll` and `resize` subscriptions. */ this._globalSubscription = null; /** Keeps track of the amount of subscriptions to `scrolled`. Used for cleaning up afterwards. */ this._scrolledCount = 0; /** * Map of all the scrollable references that are registered with the service and their * scroll event subscriptions. */ this.scrollContainers = new Map(); this._document = document; } /** * Registers a scrollable instance with the service and listens for its scrolled events. When the * scrollable is scrolled, the service emits the event to its scrolled observable. * @param scrollable Scrollable instance to be registered. */ register(scrollable) { if (!this.scrollContainers.has(scrollable)) { this.scrollContainers.set(scrollable, scrollable.elementScrolled() .subscribe(() => this._scrolled.next(scrollable))); } } /** * Deregisters a Scrollable reference and unsubscribes from its scroll event observable. * @param scrollable Scrollable instance to be deregistered. */ deregister(scrollable) { const scrollableReference = this.scrollContainers.get(scrollable); if (scrollableReference) { scrollableReference.unsubscribe(); this.scrollContainers.delete(scrollable); } } /** * Returns an observable that emits an event whenever any of the registered Scrollable * references (or window, document, or body) fire a scrolled event. Can provide a time in ms * to override the default "throttle" time. * * **Note:** in order to avoid hitting change detection for every scroll event, * all of the events emitted from this stream will be run outside the Angular zone. * If you need to update any data bindings as a result of a scroll event, you have * to run the callback using `NgZone.run`. */ scrolled(auditTimeInMs = DEFAULT_SCROLL_TIME) { if (!this._platform.isBrowser) { return of(); } return new Observable((observer) => { if (!this._globalSubscription) { this._addGlobalListener(); } // In the case of a 0ms delay, use an observable without auditTime // since it does add a perceptible delay in processing overhead. const subscription = auditTimeInMs > 0 ? this._scrolled.pipe(auditTime(auditTimeInMs)).subscribe(observer) : this._scrolled.subscribe(observer); this._scrolledCount++; return () => { subscription.unsubscribe(); this._scrolledCount--; if (!this._scrolledCount) { this._removeGlobalListener(); } }; }); } ngOnDestroy() { this._removeGlobalListener(); this.scrollContainers.forEach((_, container) => this.deregister(container)); this._scrolled.complete(); } /** * Returns an observable that emits whenever any of the * scrollable ancestors of an element are scrolled. * @param elementOrElementRef Element whose ancestors to listen for. * @param auditTimeInMs Time to throttle the scroll events. */ ancestorScrolled(elementOrElementRef, auditTimeInMs) { const ancestors = this.getAncestorScrollContainers(elementOrElementRef); return this.scrolled(auditTimeInMs).pipe(filter(target => { return !target || ancestors.indexOf(target) > -1; })); } /** Returns all registered Scrollables that contain the provided element. */ getAncestorScrollContainers(elementOrElementRef) { const scrollingContainers = []; this.scrollContainers.forEach((_subscription, scrollable) => { if (this._scrollableContainsElement(scrollable, elementOrElementRef)) { scrollingContainers.push(scrollable); } }); return scrollingContainers; } /** Use defaultView of injected document if available or fallback to global window reference */ _getWindow() { return this._document.defaultView || window; } /** Returns true if the element is contained within the provided Scrollable. */ _scrollableContainsElement(scrollable, elementOrElementRef) { let element = coerceElement(elementOrElementRef); let scrollableElement = scrollable.getElementRef().nativeElement; // Traverse through the element parents until we reach null, checking if any of the elements // are the scrollable's element. do { if (element == scrollableElement) { return true; } } while (element = element.parentElement); return false; } /** Sets up the global scroll listeners. */ _addGlobalListener() { this._globalSubscription = this._ngZone.runOutsideAngular(() => { const window = this._getWindow(); return fromEvent(window.document, 'scroll').subscribe(() => this._scrolled.next()); }); } /** Cleans up the global scroll listener. */ _removeGlobalListener() { if (this._globalSubscription) { this._globalSubscription.unsubscribe(); this._globalSubscription = null; } } } ScrollDispatcher.ɵprov = i0.ɵɵdefineInjectable({ factory: function ScrollDispatcher_Factory() { return new ScrollDispatcher(i0.ɵɵinject(i0.NgZone), i0.ɵɵinject(i1.Platform), i0.ɵɵinject(i2.DOCUMENT, 8)); }, token: ScrollDispatcher, providedIn: "root" }); ScrollDispatcher.decorators = [ { type: Injectable, args: [{ providedIn: 'root' },] } ]; ScrollDispatcher.ctorParameters = () => [ { type: NgZone }, { type: Platform }, { type: undefined, decorators: [{ type: Optional }, { type: Inject, args: [DOCUMENT,] }] } ]; /** * @license * Copyright Google LLC All Rights Reserved. * * Use of this source code is governed by an MIT-style license that can be * found in the LICENSE file at https://angular.io/license */ /** * Sends an event when the directive's element is scrolled. Registers itself with the * ScrollDispatcher service to include itself as part of its collection of scrolling events that it * can be listened to through the service. */ class CdkScrollable { constructor(elementRef, scrollDispatcher, ngZone, dir) { this.elementRef = elementRef; this.scrollDispatcher = scrollDispatcher; this.ngZone = ngZone; this.dir = dir; this._destroyed = new Subject(); this._elementScrolled = new Observable((observer) => this.ngZone.runOutsideAngular(() => fromEvent(this.elementRef.nativeElement, 'scroll').pipe(takeUntil(this._destroyed)) .subscribe(observer))); } ngOnInit() { this.scrollDispatcher.register(this); } ngOnDestroy() { this.scrollDispatcher.deregister(this); this._destroyed.next(); this._destroyed.complete(); } /** Returns observable that emits when a scroll event is fired on the host element. */ elementScrolled() { return this._elementScrolled; } /** Gets the ElementRef for the viewport. */ getElementRef() { return this.elementRef; } /** * Scrolls to the specified offsets. This is a normalized version of the browser's native scrollTo * method, since browsers are not consistent about what scrollLeft means in RTL. For this method * left and right always refer to the left and right side of the scrolling container irrespective * of the layout direction. start and end refer to left and right in an LTR context and vice-versa * in an RTL context. * @param options specified the offsets to scroll to. */ scrollTo(options) { const el = this.elementRef.nativeElement; const isRtl = this.dir && this.dir.value == 'rtl'; // Rewrite start & end offsets as right or left offsets. if (options.left == null) { options.left = isRtl ? options.end : options.start; } if (options.right == null) { options.right = isRtl ? options.start : options.end; } // Rewrite the bottom offset as a top offset. if (options.bottom != null) { options.top = el.scrollHeight - el.clientHeight - options.bottom; } // Rewrite the right offset as a left offset. if (isRtl && getRtlScrollAxisType() != 0 /* NORMAL */) { if (options.left != null) { options.right = el.scrollWidth - el.clientWidth - options.left; } if (getRtlScrollAxisType() == 2 /* INVERTED */) { options.left = options.right; } else if (getRtlScrollAxisType() == 1 /* NEGATED */) { options.left = options.right ? -options.right : options.right; } } else { if (options.right != null) { options.left = el.scrollWidth - el.clientWidth - options.right; } } this._applyScrollToOptions(options); } _applyScrollToOptions(options) { const el = this.elementRef.nativeElement; if (supportsScrollBehavior()) { el.scrollTo(options); } else { if (options.top != null) { el.scrollTop = options.top; } if (options.left != null) { el.scrollLeft = options.left; } } } /** * Measures the scroll offset relative to the specified edge of the viewport. This method can be * used instead of directly checking scrollLeft or scrollTop, since browsers are not consistent * about what scrollLeft means in RTL. The values returned by this method are normalized such that * left and right always refer to the left and right side of the scrolling container irrespective * of the layout direction. start and end refer to left and right in an LTR context and vice-versa * in an RTL context. * @param from The edge to measure from. */ measureScrollOffset(from) { const LEFT = 'left'; const RIGHT = 'right'; const el = this.elementRef.nativeElement; if (from == 'top') { return el.scrollTop; } if (from == 'bottom') { return el.scrollHeight - el.clientHeight - el.scrollTop; } // Rewrite start & end as left or right offsets. const isRtl = this.dir && this.dir.value == 'rtl'; if (from == 'start') { from = isRtl ? RIGHT : LEFT; } else if (from == 'end') { from = isRtl ? LEFT : RIGHT; } if (isRtl && getRtlScrollAxisType() == 2 /* INVERTED */) { // For INVERTED, scrollLeft is (scrollWidth - clientWidth) when scrolled all the way left and // 0 when scrolled all the way right. if (from == LEFT) { return el.scrollWidth - el.clientWidth - el.scrollLeft; } else { return el.scrollLeft; } } else if (isRtl && getRtlScrollAxisType() == 1 /* NEGATED */) { // For NEGATED, scrollLeft is -(scrollWidth - clientWidth) when scrolled all the way left and // 0 when scrolled all the way right. if (from == LEFT) { return el.scrollLeft + el.scrollWidth - el.clientWidth; } else { return -el.scrollLeft; } } else { // For NORMAL, as well as non-RTL contexts, scrollLeft is 0 when scrolled all the way left and // (scrollWidth - clientWidth) when scrolled all the way right. if (from == LEFT) { return el.scrollLeft; } else { return el.scrollWidth - el.clientWidth - el.scrollLeft; } } } } CdkScrollable.decorators = [ { type: Directive, args: [{ selector: '[cdk-scrollable], [cdkScrollable]' },] } ]; CdkScrollable.ctorParameters = () => [ { type: ElementRef }, { type: ScrollDispatcher }, { type: NgZone }, { type: Directionality, decorators: [{ type: Optional }] } ]; /** * @license * Copyright Google LLC All Rights Reserved. * * Use of this source code is governed by an MIT-style license that can be * found in the LICENSE file at https://angular.io/license */ /** Time in ms to throttle the resize events by default. */ const DEFAULT_RESIZE_TIME = 20; /** * Simple utility for getting the bounds of the browser viewport. * @docs-private */ class ViewportRuler { constructor(_platform, ngZone, document) { this._platform = _platform; /** Stream of viewport change events. */ this._change = new Subject(); /** Event listener that will be used to handle the viewport change events. */ this._changeListener = (event) => { this._change.next(event); }; this._document = document; ngZone.runOutsideAngular(() => { if (_platform.isBrowser) { const window = this._getWindow(); // Note that bind the events ourselves, rather than going through something like RxJS's // `fromEvent` so that we can ensure that they're bound outside of the NgZone. window.addEventListener('resize', this._changeListener); window.addEventListener('orientationchange', this._changeListener); } // Clear the cached position so that the viewport is re-measured next time it is required. // We don't need to keep track of the subscription, because it is completed on destroy. this.change().subscribe(() => this._viewportSize = null); }); } ngOnDestroy() { if (this._platform.isBrowser) { const window = this._getWindow(); window.removeEventListener('resize', this._changeListener); window.removeEventListener('orientationchange', this._changeListener); } this._change.complete(); } /** Returns the viewport's width and height. */ getViewportSize() { if (!this._viewportSize) { this._updateViewportSize(); } const output = { width: this._viewportSize.width, height: this._viewportSize.height }; // If we're not on a browser, don't cache the size since it'll be mocked out anyway. if (!this._platform.isBrowser) { this._viewportSize = null; } return output; } /** Gets a ClientRect for the viewport's bounds. */ getViewportRect() { // Use the document element's bounding rect rather than the window scroll properties // (e.g. pageYOffset, scrollY) due to in issue in Chrome and IE where window scroll // properties and client coordinates (boundingClientRect, clientX/Y, etc.) are in different // conceptual viewports. Under most circumstances these viewports are equivalent, but they // can disagree when the page is pinch-zoomed (on devices that support touch). // See https://bugs.chromium.org/p/chromium/issues/detail?id=489206#c4 // We use the documentElement instead of the body because, by default (without a css reset) // browsers typically give the document body an 8px margin, which is not included in // getBoundingClientRect(). const scrollPosition = this.getViewportScrollPosition(); const { width, height } = this.getViewportSize(); return { top: scrollPosition.top, left: scrollPosition.left, bottom: scrollPosition.top + height, right: scrollPosition.left + width, height, width, }; } /** Gets the (top, left) scroll position of the viewport. */ getViewportScrollPosition() { // While we can get a reference to the fake document // during SSR, it doesn't have getBoundingClientRect. if (!this._platform.isBrowser) { return { top: 0, left: 0 }; } // The top-left-corner of the viewport is determined by the scroll position of the document // body, normally just (scrollLeft, scrollTop). However, Chrome and Firefox disagree about // whether `document.body` or `document.documentElement` is the scrolled element, so reading // `scrollTop` and `scrollLeft` is inconsistent. However, using the bounding rect of // `document.documentElement` works consistently, where the `top` and `left` values will // equal negative the scroll position. const document = this._document; const window = this._getWindow(); const documentElement = document.documentElement; const documentRect = documentElement.getBoundingClientRect(); const top = -documentRect.top || document.body.scrollTop || window.scrollY || documentElement.scrollTop || 0; const left = -documentRect.left || document.body.scrollLeft || window.scrollX || documentElement.scrollLeft || 0; return { top, left }; } /** * Returns a stream that emits whenever the size of the viewport changes. * This stream emits outside of the Angular zone. * @param throttleTime Time in milliseconds to throttle the stream. */ change(throttleTime = DEFAULT_RESIZE_TIME) { return throttleTime > 0 ? this._change.pipe(auditTime(throttleTime)) : this._change; } /** Use defaultView of injected document if available or fallback to global window reference */ _getWindow() { return this._document.defaultView || window; } /** Updates the cached viewport size. */ _updateViewportSize() { const window = this._getWindow(); this._viewportSize = this._platform.isBrowser ? { width: window.innerWidth, height: window.innerHeight } : { width: 0, height: 0 }; } } ViewportRuler.ɵprov = i0.ɵɵdefineInjectable({ factory: function ViewportRuler_Factory() { return new ViewportRuler(i0.ɵɵinject(i1.Platform), i0.ɵɵinject(i0.NgZone), i0.ɵɵinject(i2.DOCUMENT, 8)); }, token: ViewportRuler, providedIn: "root" }); ViewportRuler.decorators = [ { type: Injectable, args: [{ providedIn: 'root' },] } ]; ViewportRuler.ctorParameters = () => [ { type: Platform }, { type: NgZone }, { type: undefined, decorators: [{ type: Optional }, { type: Inject, args: [DOCUMENT,] }] } ]; /** * @license * Copyright Google LLC All Rights Reserved. * * Use of this source code is governed by an MIT-style license that can be * found in the LICENSE file at https://angular.io/license */ /** Checks if the given ranges are equal. */ function rangesEqual(r1, r2) { return r1.start == r2.start && r1.end == r2.end; } /** * Scheduler to be used for scroll events. Needs to fall back to * something that doesn't rely on requestAnimationFrame on environments * that don't support it (e.g. server-side rendering). */ const SCROLL_SCHEDULER = typeof requestAnimationFrame !== 'undefined' ? animationFrameScheduler : asapScheduler; /** A viewport that virtualizes its scrolling with the help of `CdkVirtualForOf`. */ class CdkVirtualScrollViewport extends CdkScrollable { constructor(elementRef, _changeDetectorRef, ngZone, _scrollStrategy, dir, scrollDispatcher, viewportRuler) { super(elementRef, scrollDispatcher, ngZone, dir); this.elementRef = elementRef; this._changeDetectorRef = _changeDetectorRef; this._scrollStrategy = _scrollStrategy; /** Emits when the viewport is detached from a CdkVirtualForOf. */ this._detachedSubject = new Subject(); /** Emits when the rendered range changes. */ this._renderedRangeSubject = new Subject(); this._orientation = 'vertical'; this._appendOnly = false; // Note: we don't use the typical EventEmitter here because we need to subscribe to the scroll // strategy lazily (i.e. only if the user is actually listening to the events). We do this because // depending on how the strategy calculates the scrolled index, it may come at a cost to // performance. /** Emits when the index of the first element visible in the viewport changes. */ this.scrolledIndexChange = new Observable((observer) => this._scrollStrategy.scrolledIndexChange.subscribe(index => Promise.resolve().then(() => this.ngZone.run(() => observer.next(index))))); /** A stream that emits whenever the rendered range changes. */ this.renderedRangeStream = this._renderedRangeSubject; /** * The total size of all content (in pixels), including content that is not currently rendered. */ this._totalContentSize = 0; /** A string representing the `style.width` property value to be used for the spacer element. */ this._totalContentWidth = ''; /** A string representing the `style.height` property value to be used for the spacer element. */ this._totalContentHeight = ''; /** The currently rendered range of indices. */ this._renderedRange = { start: 0, end: 0 }; /** The length of the data bound to this viewport (in number of items). */ this._dataLength = 0; /** The size of the viewport (in pixels). */ this._viewportSize = 0; /** The last rendered content offset that was set. */ this._renderedContentOffset = 0; /** * Whether the last rendered content offset was to the end of the content (and therefore needs to * be rewritten as an offset to the start of the content). */ this._renderedContentOffsetNeedsRewrite = false; /** Whether there is a pending change detection cycle. */ this._isChangeDetectionPending = false; /** A list of functions to run after the next change detection cycle. */ this._runAfterChangeDetection = []; /** Subscription to changes in the viewport size. */ this._viewportChanges = Subscription.EMPTY; if (!_scrollStrategy && (typeof ngDevMode === 'undefined' || ngDevMode)) { throw Error('Error: cdk-virtual-scroll-viewport requires the "itemSize" property to be set.'); } this._viewportChanges = viewportRuler.change().subscribe(() => { this.checkViewportSize(); }); } /** The direction the viewport scrolls. */ get orientation() { return this._orientation; } set orientation(orientation) { if (this._orientation !== orientation) { this._orientation = orientation; this._calculateSpacerSize(); } } /** * Whether rendered items should persist in the DOM after scrolling out of view. By default, items * will be removed. */ get appendOnly() { return this._appendOnly; } set appendOnly(value) { this._appendOnly = coerceBooleanProperty(value); } ngOnInit() { super.ngOnInit(); // It's still too early to measure the viewport at this point. Deferring with a promise allows // the Viewport to be rendered with the correct size before we measure. We run this outside the // zone to avoid causing more change detection cycles. We handle the change detection loop // ourselves instead. this.ngZone.runOutsideAngular(() => Promise.resolve().then(() => { this._measureViewportSize(); this._scrollStrategy.attach(this); this.elementScrolled() .pipe( // Start off with a fake scroll event so we properly detect our initial position. startWith(null), // Collect multiple events into one until the next animation frame. This way if // there are multiple scroll events in the same frame we only need to recheck // our layout once. auditTime(0, SCROLL_SCHEDULER)) .subscribe(() => this._scrollStrategy.onContentScrolled()); this._markChangeDetectionNeeded(); })); } ngOnDestroy() { this.detach(); this._scrollStrategy.detach(); // Complete all subjects this._renderedRangeSubject.complete(); this._detachedSubject.complete(); this._viewportChanges.unsubscribe(); super.ngOnDestroy(); } /** Attaches a `CdkVirtualScrollRepeater` to this viewport. */ attach(forOf) { if (this._forOf && (typeof ngDevMode === 'undefined' || ngDevMode)) { throw Error('CdkVirtualScrollViewport is already attached.'); } // Subscribe to the data stream of the CdkVirtualForOf to keep track of when the data length // changes. Run outside the zone to avoid triggering change detection, since we're managing the // change detection loop ourselves. this.ngZone.runOutsideAngular(() => { this._forOf = forOf; this._forOf.dataStream.pipe(takeUntil(this._detachedSubject)).subscribe(data => { const newLength = data.length; if (newLength !== this._dataLength) { this._dataLength = newLength; this._scrollStrategy.onDataLengthChanged(); } this._doChangeDetection(); }); }); } /** Detaches the current `CdkVirtualForOf`. */ detach() { this._forOf = null; this._detachedSubject.next(); } /** Gets the length of the data bound to this viewport (in number of items). */ getDataLength() { return this._dataLength; } /** Gets the size of the viewport (in pixels). */ getViewportSize() { return this._viewportSize; } // TODO(mmalerba): This is technically out of sync with what's really rendered until a render // cycle happens. I'm being careful to only call it after the render cycle is complete and before // setting it to something else, but its error prone and should probably be split into // `pendingRange` and `renderedRange`, the latter reflecting whats actually in the DOM. /** Get the current rendered range of items. */ getRenderedRange() { return this._renderedRange; } /** * Sets the total size of all content (in pixels), including content that is not currently * rendered. */ setTotalContentSize(size) { if (this._totalContentSize !== size) { this._totalContentSize = size; this._calculateSpacerSize(); this._markChangeDetectionNeeded(); } } /** Sets the currently rendered range of indices. */ setRenderedRange(range) { if (!rangesEqual(this._renderedRange, range)) { if (this.appendOnly) { range = { start: 0, end: Math.max(this._renderedRange.end, range.end) }; } this._renderedRangeSubject.next(this._renderedRange = range); this._markChangeDetectionNeeded(() => this._scrollStrategy.onContentRendered()); } } /** * Gets the offset from the start of the viewport to the start of the rendered data (in pixels). */ getOffsetToRenderedContentStart() { return this._renderedContentOffsetNeedsRewrite ? null : this._renderedContentOffset; } /** * Sets the offset from the start of the viewport to either the start or end of the rendered data * (in pixels). */ setRenderedContentOffset(offset, to = 'to-start') { // For a horizontal viewport in a right-to-left language we need to translate along the x-axis // in the negative direction. const isRtl = this.dir && this.dir.value == 'rtl'; const isHorizontal = this.orientation == 'horizontal'; const axis = isHorizontal ? 'X' : 'Y'; const axisDirection = isHorizontal && isRtl ? -1 : 1; let transform = `translate${axis}(${Number(axisDirection * offset)}px)`; this._renderedContentOffset = offset; if (to === 'to-end') { transform += ` translate${axis}(-100%)`; // The viewport should rewrite this as a `to-start` offset on the next render cycle. Otherwise // elements will appear to expand in the wrong direction (e.g. `mat-expansion-panel` would // expand upward). this._renderedContentOffsetNeedsRewrite = true; } if (this._renderedContentTransform != transform) { // We know this value is safe because we parse `offset` with `Number()` before passing it // into the string. this._renderedContentTransform = transform; this._markChangeDetectionNeeded(() => { if (this._renderedContentOffsetNeedsRewrite) { this._renderedContentOffset -= this.measureRenderedContentSize(); this._renderedContentOffsetNeedsRewrite = false; this.setRenderedContentOffset(this._renderedContentOffset); } else { this._scrollStrategy.onRenderedOffsetChanged(); } }); } } /** * Scrolls to the given offset from the start of the viewport. Please note that this is not always * the same as setting `scrollTop` or `scrollLeft`. In a horizontal viewport with right-to-left * direction, this would be the equivalent of setting a fictional `scrollRight` property. * @param offset The offset to scroll to. * @param behavior The ScrollBehavior to use when scrolling. Default is behavior is `auto`. */ scrollToOffset(offset, behavior = 'auto') { const options = { behavior }; if (this.orientation === 'horizontal') { options.start = offset; } else { options.top = offset; } this.scrollTo(options); } /** * Scrolls to the offset for the given index. * @param index The index of the element to scroll to. * @param behavior The ScrollBehavior to use when scrolling. Default is behavior is `auto`. */ scrollToIndex(index, behavior = 'auto') { this._scrollStrategy.scrollToIndex(index, behavior); } /** * Gets the current scroll offset from the start of the viewport (in pixels). * @param from The edge to measure the offset from. Defaults to 'top' in vertical mode and 'start' * in horizontal mode. */ measureScrollOffset(from) { return from ? super.measureScrollOffset(from) : super.measureScrollOffset(this.orientation === 'horizontal' ? 'start' : 'top'); } /** Measure the combined size of all of the rendered items. */ measureRenderedContentSize() { const contentEl = this._contentWrapper.nativeElement; return this.orientation === 'horizontal' ? contentEl.offsetWidth : contentEl.offsetHeight; } /** * Measure the total combined size of the given range. Throws if the range includes items that are * not rendered. */ measureRangeSize(range) { if (!this._forOf) { return 0; } return this._forOf.measureRangeSize(range, this.orientation); } /** Update the viewport dimensions and re-render. */ checkViewportSize() { // TODO: Cleanup later when add logic for handling content resize this._measureViewportSize(); this._scrollStrategy.onDataLengthChanged(); } /** Measure the viewport size. */ _measureViewportSize() { const viewportEl = this.elementRef.nativeElement; this._viewportSize = this.orientation === 'horizontal' ? viewportEl.clientWidth : viewportEl.clientHeight; } /** Queue up change detection to run. */ _markChangeDetectionNeeded(runAfter) { if (runAfter) { this._runAfterChangeDetection.push(runAfter); } // Use a Promise to batch together calls to `_doChangeDetection`. This way if we set a bunch of // properties sequentially we only have to run `_doChangeDetection` once at the end. if (!this._isChangeDetectionPending) { this._isChangeDetectionPending = true; this.ngZone.runOutsideAngular(() => Promise.resolve().then(() => { this._doChangeDetection(); })); } } /** Run change detection. */ _doChangeDetection() { this._isChangeDetectionPending = false; // Apply the content transform. The transform can't be set via an Angular binding because // bypassSecurityTrustStyle is banned in Google. However the value is safe, it's composed of // string literals, a variable that can only be 'X' or 'Y', and user input that is run through // the `Number` function first to coerce it to a numeric value. this._contentWrapper.nativeElement.style.transform = this._renderedContentTransform; // Apply changes to Angular bindings. Note: We must call `markForCheck` to run change detection // from the root, since the repeated items are content projected in. Calling `detectChanges` // instead does not properly check the projected content. this.ngZone.run(() => this._changeDetectorRef.markForCheck()); const runAfterChangeDetection = this._runAfterChangeDetection; this._runAfterChangeDetection = []; for (const fn of runAfterChangeDetection) { fn(); } } /** Calculates the `style.width` and `style.height` for the spacer element. */ _calculateSpacerSize() { this._totalContentHeight = this.orientation === 'horizontal' ? '' : `${this._totalContentSize}px`; this._totalContentWidth = this.orientation === 'horizontal' ? `${this._totalContentSize}px` : ''; } } CdkVirtualScrollViewport.decorators = [ { type: Component, args: [{ selector: 'cdk-virtual-scroll-viewport', template: "\n