@equinor/fusion-observable/dist/types/FlowSubject.d.ts

WIP

import type { Reducer } from 'react';
import { Observable, type Subscription } from 'rxjs';
import type { Action, ActionType, ExtractAction } from './types/actions';
import type { Flow, Effect } from './types/flow';
import type { ReducerWithInitialState } from './types/reducers';
/**
 * A specialized Observable that maintains internal state, which can be mutated by dispatching actions.
 * Actions are processed sequentially by a reducer function to produce new state values.
 * This class extends from Observable to allow subscribers to react to state changes over time.
 */
export declare class FlowSubject<S, A extends Action = Action> extends Observable<S> {
    #private;
    /**
     * Observable stream of actions dispatched to the subject.
     */
    get action$(): Observable<A>;
    /**
     * The current value of state.
     */
    get value(): S;
    /**
     * Flag to indicate if the observable is closed.
     */
    get closed(): boolean;
    /**
     * Creates a new instance of the FlowSubject class with an initial state reducer.
     * @param reducer A reducer with an initial state or a reducer function.
     */
    constructor(reducer: ReducerWithInitialState<S, A>);
    /**
     * Create a new instance of the FlowSubject class with a reducer function and initial state.
     * @param reducer state reducer
     * @param initialState initial state
     */
    constructor(reducer: Reducer<S, A>, initialState: S);
    /**
     * Resets the state to the initial value.
     */
    reset: VoidFunction;
    /**
     * Dispatches an action to the subject.
     *
     * @param action The action to dispatch.
     */
    next(action: A): void;
    /**
     * Selects a derived state from the observable state and emits only when the selected state changes.
     *
     * @param selector - A function that takes the current state and returns a derived state.
     * @param comparator - An optional function that compares the previous and current derived states to determine if a change has occurred.
     * @returns An observable that emits the derived state whenever it changes.
     */
    select<T>(selector: (state: S) => T, comparator?: (previous: T, current: T) => boolean): Observable<T>;
    /**
     * Adds an effect that listens for actions and performs side effects.
     *
     * @param fn The effect function to execute.
     * @returns A subscription to the effect.
     */
    addEffect(fn: Effect<A, S>): Subscription;
    /**
     * Adds an effect that listens for a specific action type and performs side effects.
     *
     * @param actionType The type of action to listen for.
     * @param cb The effect function to execute when the action is dispatched.
     * @returns A subscription to the effect.
     */
    addEffect<TType extends ActionType<A>>(actionType: TType, cb: Effect<ExtractAction<A, NoInfer<TType>>, S>): Subscription;
    /**
     * Adds an effect that listens for an array of action types and performs side effects.
     *
     * @param actionType The array of action types to listen for.
     * @param cb The effect function to execute when one of the actions is dispatched.
     * @returns A subscription to the effect.
     */
    addEffect<TType extends ActionType<A>>(actionType: Array<TType>, cb: Effect<ExtractAction<A, NoInfer<TType>>, S>): Subscription;
    /**
     * Deprecated. Use `addFlow` instead.
     *
     * @deprecated use `addFlow`
     *
     * @param fn The flow function to execute.
     * @returns A subscription to the flow.
     */
    addEpic(fn: Flow<A, S>): Subscription;
    /**
     * Adds a flow that listens for actions and performs side effects.
     *
     * @param fn The flow function to execute.
     * @returns A subscription to the flow.
     */
    addFlow(fn: Flow<A, S>): Subscription;
    /**
     * Unsubscribes from actions and removes subscribers.
     */
    unsubscribe(): void;
    /**
     * Finalizes the subject and completes observers.
     */
    complete(): void;
    /**
     * Clones the subject to a simple observable.
     *
     * @returns An observable of the state.
     */
    asObservable(): Observable<S>;
}
export default FlowSubject;