import { Dispatch } from 'react';
/**
 * The type used to store workers in the state.
 */
export declare type Worker = {
    [identifier: string]: Record<string, unknown>;
} | (Record<string, unknown> | undefined);
/**
 * The state is composed of:
 * - a cache, which is a simple object with strings as keys and typed values;
 * - the workers currently loading elements.
 */
export interface State<V, W extends Worker> {
    cache: {
        [identifier: string]: V | undefined;
    };
    worker: W;
}
/**
 * Type of actions which can be applied to the state.
 */
export declare const enum ActionType {
    AddElement = 0,
    StartWorking = 1,
    StopWorking = 2
}
/**
 * The action used to add an element.
 */
interface AddElementAction<V> {
    type: ActionType.AddElement;
    payload: {
        identifier: string;
        element: V | undefined;
    };
}
/**
 * Create an action used to add an element.
 *
 * @param (unnamed) - The element to add.
 * @param (unnamed).identifier - The element identifier.
 * @param (unnamed).element - The element to add.
 * @returns The appropriate action.
 */
export declare function addElement<V>({ identifier, element, }: {
    identifier: string;
    element: V | undefined;
}): AddElementAction<V>;
/**
 * The action used to start working.
 */
interface StartWorkingAction {
    type: ActionType.StartWorking;
    payload: {
        identifier: string;
        worker: Record<string, unknown>;
    };
}
/**
 * Create an action used to start working.
 *
 * @param identifier - The element identifier.
 * @param worker - Any object, used to uniquely identify the worker.
 * @returns The appropriate action.
 */
export declare function startWorking(identifier: string, worker: Record<string, unknown>): StartWorkingAction;
/**
 * The action used to stop working.
 */
interface StopWorkingAction {
    type: ActionType.StopWorking;
    payload: {
        identifier: string;
        worker: Record<string, unknown>;
    };
}
/**
 * Create an action used to stop working.
 *
 * @param identifier - The element identifier.
 * @param worker - The object used to uniquely identify the worker.
 * @returns The appropriate action.
 */
export declare function stopWorking(identifier: string, worker: Record<string, unknown>): StopWorkingAction;
/**
 * The action expected by the reducer.
 */
export declare type Action<V> = AddElementAction<V> | StartWorkingAction | StopWorkingAction;
/**
 * Alias for the useReducer return type.
 */
declare type ReducerSystem<V, W extends Worker> = [State<V, W>, Dispatch<Action<V>>];
export default ReducerSystem;