import { Action } from '@ngrx/store/src/models';
import { ActionFactoryResult, CombinedLoadingState, FailureAction, FailureHandlerState, LoadAction, LoadingState } from './loading-state-types';
/**
 * See if a new API fetch should be issued.
 *
 * @param currentState The current loading state.
 * @param action The the LoadAction dispatched by the user.
 * @returns True if a new API fetch should be issued.
 */
export declare function shouldIssueFetch(currentState: Readonly<LoadingState>, action: Readonly<LoadAction>): boolean;
/**
 * Return the type of error handler that should be used.
 *
 * @param currentState the current state
 * @param action the load action dispatched by the user
 * @param issueFetch whether the load action should issue a new API call.
 * @returns
 */
export declare function getFailureHandlerState(currentState: Readonly<LoadingState>, action: Readonly<LoadAction>, issueFetch: boolean): FailureHandlerState;
/**
 * This function make it easier to define the type of prop<T>. Internal use only.
 *
 * T extends object meets the condition of props function
 *
 * ref: https://stackoverflow.com/questions/65888508/how-to-use-generic-type-in-ngrx-createaction-props
 *
 * @param type String type of the action
 * @returns An action creator function
 */
export declare function actionFactory<T extends object>(type: string): ActionFactoryResult<T>;
/**
 * Make a clone of any object that implements the LoadingState interface, but copy over only
 * those fields that are in the LoadingState interface.
 *
 * @param src Any object that implements the LoadingState interface
 * @returns A copy of src with only fields from LoadingState
 */
export declare function cloneLoadingState(src: LoadingState): LoadingState;
/**
 * Combine the currentState and the user dispatched LoadAction into newState.
 *
 * @param action User dispatched LoadAction
 * @param currentState Current store state
 * @returns A new state if the state should change, null otherwise.
 */
export declare function getNewLoadState(action: LoadAction & Action, currentState: LoadingState): Readonly<LoadingState> | null;
/**
 * @returns Always returns a new success state.
 */
export declare function getNewSuccessState(): Readonly<LoadingState>;
/**
 * Returns a new FailureState.
 *
 * @param action User dispatched FailureAction
 * @param currentState Current loading state
 * @returns A new loading state.
 */
export declare function getNewFailureState(action: FailureAction & Action, currentState: LoadingState): Readonly<LoadingState>;
export declare function combineLoadingStates(loadingStates: LoadingState[]): CombinedLoadingState;