import type { ComponentDef, EntityHandle, FieldValue, Schema, SchemaOf } from '@ecsia/schema';
import { onAdd } from '../reactivity/index.js';
interface StableIndexWorld {
    observe(term: ReturnType<typeof onAdd>, handler: (e: {
        handle: EntityHandle;
        read(def: unknown): unknown;
    }) => void): {
        dispose(): void;
    };
    decodeHandle(handle: EntityHandle): {
        index: number;
    };
}
export interface StableIndex<K> {
    /** The entity currently holding stable id `k`, or undefined. */
    get(k: K): EntityHandle | undefined;
    /** Does some live entity hold `k`? */
    has(k: K): boolean;
    /** Stop observing and clear the index. */
    dispose(): void;
}
/**
 * Build a world-level `idField → entity` index over a component carrying a stable id field. Maintained
 * via onAdd/onRemove: when the component is added, its id field is read and the entity recorded; when
 * removed (or the entity despawned), the mapping is dropped. Last writer wins on collision.
 */
export declare function createStableIndex<C extends ComponentDef<Schema>, F extends keyof SchemaOf<C> & string>(world: StableIndexWorld, component: C, idField: F): StableIndex<FieldValue<SchemaOf<C>[F]>>;
export {};
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