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interfaces.ts
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interfaces.ts
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import { Binding, Scope, ICollectionObserverSplice, ObserverLocator, InternalCollectionObserver, OverrideContext } from 'aurelia-binding';
import { TaskQueue } from 'aurelia-task-queue';
import { View, ViewSlot, Controller } from 'aurelia-templating';
import { AbstractRepeater } from 'aurelia-templating-resources';
export interface IScrollNextScrollContext {
topIndex: number;
isAtBottom: boolean;
isAtTop: boolean;
}
/**@internal */
declare module 'aurelia-binding' {
interface ObserverLocator {
taskQueue: TaskQueue;
}
interface OverrideContext {
$index: number;
$scrollContext: IScrollNextScrollContext;
$first: boolean;
$last: boolean;
$middle: boolean;
$odd: boolean;
$even: boolean;
}
}
/**@internal */
declare module 'aurelia-templating' {
interface View {
firstChild: Node & { au?: any };
lastChild: Node & { au?: any };
bindings: Binding[];
controllers: Controller[];
}
interface Controller {
boundProperties: { binding: Binding }[];
}
}
export interface IVirtualRepeater extends AbstractRepeater {
items: any;
local?: string;
/**
* First view index, for proper follow up calculations
*/
$first: number;
/**
* Defines how many items there should be for a given index to be considered at edge
*/
edgeDistance: number;
/**
* Template handling strategy for this repeat.
*/
templateStrategy: ITemplateStrategy;
/**
* The element hosting the scrollbar for this repeater
*/
scrollerEl: HTMLElement;
/**
* Top buffer element, used to reflect the visualization of amount of items `before` the first visible item
* @internal
*/
topBufferEl: HTMLElement;
/**
* Bot buffer element, used to reflect the visualization of amount of items `after` the first visible item
*/
bottomBufferEl: HTMLElement;
/**
* Height of top buffer to properly push the visible rendered list items into right position
* Usually determined by `_first` visible index * `itemHeight`
*/
topBufferHeight: number;
/**
* Height of bottom buffer to properly push the visible rendered list items into right position
*/
bottomBufferHeight: number;
/**
* Height of each item. Calculated based on first item
*/
itemHeight: number;
/**
* Calculate current scrolltop position
*/
distanceToTop: number;
/**
* Number indicating minimum elements required to render to fill up the visible viewport
*/
minViewsRequired: number;
// /**
// * Indicates whether virtual repeat attribute is inside a fixed height container with overflow
// *
// * This helps identifies place to add scroll event listener
// */
// fixedHeightContainer: boolean;
/**
* ViewSlot that encapsulates the repeater views operations in the template
*/
readonly viewSlot: ViewSlot;
/**
* Aurelia change handler by convention for property `items`. Used to properly determine action
* needed when items value has been changed
*/
itemsChanged(): void;
/**
* Get first visible view
*/
firstView(): IView | null;
/**
* Get last visible view
*/
lastView(): IView | null;
/**
* Get index of first visible view
*/
firstViewIndex(): number;
/**
* Get index of last visible view
*/
lastViewIndex(): number;
/**
* Virtual repeater normally employs scroll handling buffer for performance reasons.
* As syncing between scrolling state and visible views could be expensive.
*/
enableScroll(): void;
/**
* Invoke infinite scroll next function expression with currently bound scope of the repeater
*/
getMore(topIndex: number, isNearTop: boolean, isNearBottom: boolean, force?: boolean): void;
/**
* Get the real scroller element of the DOM tree this repeat resides in
*/
getScroller(): HTMLElement;
/**
* Get scrolling information of the real scroller element of the DOM tree this repeat resides in
*/
getScrollerInfo(): IScrollerInfo;
/**
* Observe scroller element to react upon sizing changes
*/
observeScroller(scrollerEl: HTMLElement): void;
/**
* Dispose scroller content size observer, if has
* Dispose all event listeners related to sizing of scroller, if any
*/
unobserveScroller(): void;
/**
* Signal the repeater to reset all its internal calculation states.
* Typically used when items value is null, undefined, empty collection.
* Or the repeater has been detached
*/
resetCalculation(): void;
/**
* Update buffer elements height/width with corresponding
* @param skipUpdate `true` to signal this repeater that the update won't trigger scroll event
*/
updateBufferElements(skipUpdate?: boolean): void;
}
export type RepeatableValue = number | any[] | Map<any, any> | Set<any>;
export interface IVirtualRepeatStrategy<T extends RepeatableValue = RepeatableValue> {
/**
* create first item to calculate the heights
*/
createFirstRow(repeat: IVirtualRepeater): IView;
/**
* Count the number of the items in the repeatable value `items`
*/
count(items: T): number;
/**
* Calculate required variables for a virtual repeat instance to operate properly
*
* @returns `false` to notify that calculation hasn't been finished
*/
initCalculation(repeat: IVirtualRepeater, items: T): VirtualizationCalculation;
/**
* Handle special initialization if any, depends on different strategy
*/
onAttached(repeat: IVirtualRepeater): void;
/**
* Calculate the start and end index of a repeat based on its container current scroll position
*/
getViewRange(repeat: IVirtualRepeater, scrollerInfo: IScrollerInfo): [number, number];
/**
* Returns true if first index is approaching start of the collection
* Virtual repeat can use this to invoke infinite scroll next
*/
isNearTop(repeat: IVirtualRepeater, firstIndex: number): boolean;
/**
* Returns true if last index is approaching end of the collection
* Virtual repeat can use this to invoke infinite scroll next
*/
isNearBottom(repeat: IVirtualRepeater, lastIndex: number): boolean;
/**
* Update repeat buffers height based on repeat.items
*/
updateBuffers(repeat: IVirtualRepeater, firstIndex: number): void;
/**
* Get the observer based on collection type of `items`
*/
getCollectionObserver(observerLocator: ObserverLocator, items: T): InternalCollectionObserver;
/**
* @override
* Handle the repeat's collection instance changing.
* @param repeat The repeater instance.
* @param items The new array instance.
* @param firstIndex The index of first active view
*/
instanceChanged(repeat: IVirtualRepeater, items: T, firstIndex?: number): void;
/**
* @override
* Handle the repeat's collection instance mutating.
* @param repeat The virtual repeat instance.
* @param items The modified array.
* @param splices Records of array changes.
*/
instanceMutated(repeat: IVirtualRepeater, items: RepeatableValue, splices: ICollectionObserverSplice[]): void;
/**
* Unlike normal repeat, virtualization repeat employs "padding" elements. Those elements
* often are just blank block with proper height/width to adjust the height/width/scroll feeling
* of virtualized repeat.
*
* Because of this, either mutation or change of the collection of repeat will potentially require
* readjustment (or measurement) of those blank block, based on scroll position
*
* This is 2 phases scroll handle
*/
remeasure(repeat: IVirtualRepeater): void;
/**
* Update all visible views of a repeater, starting from given `startIndex`
*/
updateAllViews(repeat: IVirtualRepeater, startIndex: number): void;
}
/**
* Templating strategy to handle virtual repeat views
* Typically related to moving views, creating buffer and locating view range range in the DOM
*/
export interface ITemplateStrategy {
/**
* Determine the scroll container of a [virtual-repeat] based on its anchor (`element` is a comment node)
*/
getScrollContainer(element: Element): HTMLElement;
/**
* Move root element of a view to first position in the list, after top buffer
* Note: [virtual-repeat] only supports single root node repeat
*/
moveViewFirst(view: View, topBuffer: Element): void;
/**
* Move root element of a view to last position in the list, before bottomBuffer
* Note: [virtual-repeat] only supports single root node repeat
*/
moveViewLast(view: View, bottomBuffer: Element): void;
/**
* Create top and bottom buffer elements for an anchor (`element` is a comment node)
*/
createBuffers(element: Element): [HTMLElement, HTMLElement];
/**
* Clean up buffers of a [virtual-repeat]
*/
removeBuffers(element: Element, topBuffer: Element, bottomBuffer: Element): void;
/**
* Get the first element(or view) between top buffer and bottom buffer
* Note: [virtual-repeat] only supports single root node repeat
*/
getFirstElement(topBufer: Element, botBuffer: Element): Element;
/**
* Get the last element(or view) between top buffer and bottom buffer
* Note: [virtual-repeat] only supports single root node repeat
*/
getLastElement(topBuffer: Element, bottomBuffer: Element): Element;
}
/**
* Override `bindingContext` and `overrideContext` on `View` interface
*/
export type IView = View & Scope;
/**
* Expose property `children` to help manipulation/calculation
*/
export type IViewSlot = ViewSlot & { children: IView[] };
/**
* Ability to have strong typings on bindingContext for OverrideContext
*/
export interface IOverrideContext<T> extends OverrideContext {
bindingContext: T;
}
/**
* Object with information about current state of a scrollable element
* Capturing:
* - current scroll height
* - current scroll top
* - real height
*/
export interface IScrollerInfo {
scroller: HTMLElement;
// scrollHeight: number;
scrollTop: number;
height: number;
}
export const enum VirtualizationCalculation {
none = 0b0_00000,
reset = 0b0_00001,
has_sizing = 0b0_00010,
observe_scroller = 0b0_00100,
}
export interface IElement {
au: {
controller: Controller;
[key: string]: any;
};
}
/**
* List of events that can be used to notify virtual repeat that size has changed
*/
export const VirtualizationEvents = Object.assign(Object.create(null), {
scrollerSizeChange: 'virtual-repeat-scroller-size-changed' as const,
itemSizeChange: 'virtual-repeat-item-size-changed' as const,
}) as {
scrollerSizeChange: 'virtual-repeat-scroller-size-changed';
itemSizeChange: 'virtual-repeat-item-size-changed';
};
export const enum ScrollingState {
none = 0,
isScrollingDown = 0b0_00001,
isScrollingUp = 0b0_00010,
isNearTop = 0b0_00100,
isNearBottom = 0b0_01000,
/**@internal */
isScrollingDownAndNearBottom = isScrollingDown | isNearBottom,
/**@internal */
isScrollingUpAndNearTop = isScrollingUp | isNearTop,
}
// export const enum IVirtualRepeatState {
// isAtTop = 0b0_000000_000,
// isLastIndex = 0b0_000000_000,
// scrollingDown = 0b0_000000_000,
// scrollingUp = 0b0_000000_000,
// switchedDirection = 0b0_000000_000,
// isAttached = 0b0_000000_000,
// ticking = 0b0_000000_000,
// fixedHeightContainer = 0b0_000000_000,
// hasCalculatedSizes = 0b0_000000_000,
// calledGetMore = 0b0_000000_000,
// skipNextScrollHandle = 0b0_000000_000,
// handlingMutations = 0b0_000000_000,
// isScrolling = 0b0_000000_000
// }