API Reference

StateManagerclass

Central reactive registry that bridges your model with the rs-x expression runtime. When you call watchState(context, index), StateManager wraps the value at context[index] in an observer/proxy, begins tracking mutations, and emits on changed whenever the value meaningfully changes. Watches are reference-counted — each watchState call must be paired with a corresponding releaseState call to avoid memory leaks.

Overview

Core state tracking module. Contains StateManager (the runtime implementation), IStateManager (its contract), the IStateChange and IContextChanged event payloads, IStateOptions for configuring recursive watches, and IStateEventListener for low-level keyed callbacks.

When to use

The rsx() expression runtime calls watchState and releaseState automatically for every leaf node it observes, so most application code never touches StateManager directly. You need to call it yourself in two cases: (1) **computed / derived properties** — store derived values with setState and expose them via a getter using getState, so the expression runtime can observe them as if they were plain model fields; (2) **custom data type integration** — call watchState directly when wiring a custom observer/proxy stack into the reactive graph.

Quick facts

Kind: class
Module: state-manager
Implements: IStateManager
Members: 12
Package: @rs-x/core
Source: state-manager/state-manager.ts

Import

import { StateManager } from '@rs-x/state-manager';

Example

import { InjectionContainer } from '@rs-x/core';
import {
  RsXStateManagerModule,
  RsXStateManagerInjectionTokens,
  watchIndexRecursiveRule,
  type IStateChange,
  type IStateManager,
} from '@rs-x/state-manager';

await InjectionContainer.load(RsXStateManagerModule);

const stateManager = InjectionContainer.get<IStateManager>(
  RsXStateManagerInjectionTokens.IStateManager,
);

// ── 1. Watch a plain property ────────────────────────────────
const model = { x: { y: 10 } };

// watchState returns the current value and starts observing.
const current = stateManager.watchState(model, 'x');
console.log(current); // { y: 10 }

Constructor injection example

import { Inject } from '@rs-x/core';
import {
  RsXStateManagerInjectionTokens,
  type IStateManager,
} from '@rs-x/state-manager';

class MyConsumer {
  constructor(
    @Inject(RsXStateManagerInjectionTokens.IStateManager)
    private readonly dependency: IStateManager,
  ) {}
}

Members

12 members in this class.

readonly changed

propertypublicreadonly

readonly changed: Observable<IStateChange>

Type

Observable<IStateChange>

readonly contextChanged

propertypublicreadonly

readonly contextChanged: Observable<IContextChanged>

Type

Observable<IContextChanged>

readonly endChangeCycle

propertypublicreadonly

readonly endChangeCycle: Observable<IChangeCycleIndex>

Type

Observable<IChangeCycleIndex>

readonly startChangeCycle

propertypublicreadonly

readonly startChangeCycle: Observable<IChangeCycleIndex>

Type

Observable<IChangeCycleIndex>

clear

methodpublic

clear(): void

Parameters

No parameters.

Returns

void

getState

methodpublic

getState<T>(
  context: unknown,
  index: unknown
): T

Parameters

Name	Type	Required
context	unknown	required
index	unknown	required

Returns

isWatched

methodpublic

isWatched(
  context: unknown,
  index: unknown,
  indexWatchRule?: IIndexWatchRule
): boolean

Parameters

Name	Type	Required
context	unknown	required
index	unknown	required
indexWatchRule?	IIndexWatchRule	optional

Returns

boolean

releaseState

methodpublic

releaseState(
  context: unknown,
  index: unknown,
  indexWatchRule?: IIndexWatchRule
): void

Parameters

Name	Type	Required
context	unknown	required
index	unknown	required
indexWatchRule?	IIndexWatchRule	optional

Returns

void

setState

methodpublic

setState<T>(
  context: unknown,
  index: unknown,
  value: T,
  ownerId?: unknown
): void

Parameters

Name	Type	Required
context	unknown	required
index	unknown	required
value	T	required
ownerId?	unknown	optional

Returns

void

subscribeStateEvents

methodpublic

subscribeStateEvents(
  context: unknown,
  index: unknown,
  listener: IStateEventListener
): () => void

Parameters

Name	Type	Required
context	unknown	required
index	unknown	required
listener	IStateEventListener	required

Returns

() => void

toString

methodpublic

toString(): string

Parameters

No parameters.

Returns

string

watchState

methodpublic

watchState(
  context: unknown,
  index: unknown,
  options?: IStateOptions
): unknown

Parameters

Name	Type	Required
context	unknown	required
index	unknown	required
options?	IStateOptions	optional

Returns

unknown