import { StructuralDirective } from './structural.directive';
import { TemplateResult } from '../../processor/template-result';
/**
 * Configuration passed to the #virtualScroll directive.
 */
export interface VirtualScrollDirectiveConfig<T = unknown> {
    /** Full list of items */
    items: readonly T[];
    /** Fixed height of each item in pixels */
    itemHeight: number;
    /** Height of the scrollable container in pixels */
    containerHeight: number;
    /** Render function for each visible item */
    render: (item: T, index: number) => TemplateResult;
    /** Extra items above/below the visible area (default: 3) */
    overscan?: number;
}
/**
 * Structural directive that virtualizes a list, rendering only the visible
 * items. Manages its own scroll container, spacer, and content region.
 *
 * Usage:
 * ```html
 * <div #virtualScroll=${{
 *   items: this.items,
 *   itemHeight: 40,
 *   containerHeight: 400,
 *   render: (item, i) => html`<div class="row">${item.name}</div>`,
 *   overscan: 3
 * }}></div>
 * ```
 */
export declare class VirtualScrollDirective extends StructuralDirective {
    private scrollContainer;
    private spacer;
    private contentWrapper;
    private childInstances;
    private config;
    private scrollTop;
    private rafId;
    private get processor();
    mount(element: Element): void;
    update(value: unknown): Promise<void>;
    unmount(): void;
    protected updateContent(_value: unknown): void;
    private onScroll;
    private renderSlice;
    private clearChildren;
}
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