import { type IStream } from '../../stream/index.js';
export declare enum PromiseStatus {
    DONE = 0,
    PENDING = 1,
    ERROR = 2
}
export type PromiseStateDone<T> = {
    status: PromiseStatus.DONE;
    value: T;
};
export type PromiseStatePending = {
    status: PromiseStatus.PENDING;
};
export type PromiseStateError = {
    status: PromiseStatus.ERROR;
    error: unknown;
};
export type PromiseState<T> = PromiseStateDone<T> | PromiseStatePending | PromiseStateError;
/**
 * Lift a stream of promises into a stream of `{ status, value | error }`
 * snapshots. Latest-wins: if a new promise arrives before the previous one
 * settles, the older promise's eventual resolution is silently dropped.
 *
 * source:       -p-q|
 * p resolves:   -----a       (stale; identity check drops)
 * q resolves:   --------b
 * promiseState: -P------D|
 *   where P = { status: PENDING }
 *         D = { status: DONE, value: 'b' }
 */
export declare const promiseState: <T>(source: IStream<Promise<T>>) => IStream<PromiseState<T>>;