import type { MaybePromise } from './internal.cjs';
/**
 * A function used in `collect` methods to collect values from a collection. This is basically a single-pass map and filter.
 * @param value - the input value
 * @param index - the index of the input value
 * @param skip - a token that can be returned to skip the value
 * @param halt - a function that, when called, ensures no more values are passed
 * @returns either a new value to collect, or the `skip` token indicating to skip the value
 */
export type CollectFun<T, R> = (value: T, index: number, skip: CollectFun.Skip, halt: () => void) => R | CollectFun.Skip;
export declare namespace CollectFun {
    /**
     * Indicates, when returned from a collect function, to skip the value.
     */
    const Skip: unique symbol;
    /**
     * Indicates, when returned from a collect function, to skip the value.
     */
    type Skip = typeof Skip;
}
/**
 * A potentially asynchronous function used in `collect` methods to collect values from a collection. This is basically a single-pass map and filter.
 * @param value - the input value
 * @param index - the index of the input value
 * @param skip - a token that can be returned to skip the value
 * @param halt - a function that, when called, ensures no more values are passed
 * @returns either a new value to collect, or the `skip` token indicating to skip the value
 */
export type AsyncCollectFun<T, R> = (value: T, index: number, skip: CollectFun.Skip, halt: () => void) => MaybePromise<R | CollectFun.Skip>;