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API

Reference for the public API exported by @rdlabo/ngx-cdk-scroll-strategies v21.6.2.

Directive

directive CdkDynamicSizeVirtualScroll

Installs the dynamic-size strategy on a CDK virtual-scroll viewport.

Input Type Description Default
itemDynamicSizes itemDynamicSize[] Exact size model for the list items. []
minBufferPx number Minimum remaining buffer before rendering more items. 100
maxBufferPx number Target buffer rendered when replenishing. 200
isReverse boolean Enables reverse virtual scrolling. false
scrollOffset number Read-only normalized offset for reverse scrolling.

Classes

class DynamicSizeVirtualScrollStrategy

Implements Angular CDK VirtualScrollStrategy for item sizes known in advance.

Member Type Description
constructor (itemSize, minBufferPx, maxBufferPx, isReverse) Creates the strategy with its size model and buffer limits.
updateItemAndBufferSize (itemDynamicSize[], number, number, boolean) => void Replaces the size model and buffer configuration.
scrollToIndex (index: number, behavior: ScrollBehavior) => void Scrolls to an item index.
scrolledIndexChange Observable<number> Emits the currently scrolled index.
measureScrollOffset number Last normalized scroll offset.

class DynamicSizeVirtualScrollService

Provides viewport lifecycle, item-height binding, refresh, and smooth-scroll helpers.

Member Type Description
onInit (viewport, latestScrollOffset) => void Restores viewport state.
onDestroy (viewport) => number Captures the offset for later restoration.
getBindDynamicItemHeight (sizes: Signal<itemDynamicSize[]>) => Signal<string[]> Converts item sizes into CSS heights.
refreshViewport (viewport) => void Forces viewport dimensions to refresh.
scrollToTopSmooth (viewport) => Promise<void> Smoothly scrolls to the top.
scrollToPoint (viewport, x, y, duration?) => Promise<void> Smoothly scrolls to a point.

Functions

function sumItemSize

(dynamicSize: itemDynamicSize[], endIndex: number) => number

Returns the cumulative size of all items before endIndex.

function calculateItemCountForPixelDistance

(dynamicSize: itemDynamicSize[], itemSizeRange: number, startIndex?: number, isReverse?: boolean) => number

Converts a pixel distance into an exact fractional item count.

function calcIndex

(dynamicSize: itemDynamicSize[], itemSizeRange: number, startIndex?: number, isReverse?: boolean) => number

Legacy compatibility calculation. Use calculateItemCountForPixelDistance for continuous results.

Types

interface itemDynamicSize

Prop Type Description
itemSize number Exact item size in pixels.
consumer metadata `Record<string, string number>`