StateBus Core

Platform-agnostic core types and runtime for StateBus.

Use this package for:

• module augmentation of States and Events
• reducers, listeners, and typed state access
• ManualStateBus in tests and non-DOM environments
• computed() helpers that do not depend on React

If you are building a React app, import from @smoothbricks/statebus-react for the app-facing package surface.

Install

bun add @smoothbricks/statebus-core

Define Your App Types

Declare your application States and Events by augmenting @smoothbricks/statebus-core:

declare module '@smoothbricks/statebus-core' {
  interface States {
    counter: number;
    post: ByID<{ title: string; body: string }>;
  }

  interface Events {
    count: {
      increment: number;
      decrement: number;
    };
  }
}

Make sure the declaration file is included by TypeScript.

Basic Usage

import { ManualStateBus } from '@smoothbricks/statebus-core';

const bus = new ManualStateBus({
  initialState: {
    counter: 0,
  },
  reducers: {
    count: {
      increment: (state, payload) => {
        state.counter.update((value) => value + payload);
      },
      decrement: (state, payload) => {
        state.counter.update((value) => value - payload);
      },
    },
  },
});

bus.publish({ topic: 'count', type: 'increment', payload: 1 });
bus.dispatchEvents();

Derived State

import { computed, ManualStateBus } from '@smoothbricks/statebus-core';

const bus = new ManualStateBus({
  initialState: { counter: 0 },
  reducers: {},
});

const doubledCounter = computed(bus, 'doubledCounter', (state) => state.counter.get() * 2, undefined);

Public Exports

@smoothbricks/statebus-core exports the platform-agnostic surface, including:

• StateBus
• ManualStateBus
• computed
• sortedKeyValuePairs
• bus, event, state, and reducer types
• Computed, Atom, and related signal-adjacent types needed by consumers

Migration From @smoothbricks/statebus

The legacy monolithic package has been removed.

• declare module '@smoothbricks/statebus' -> declare module '@smoothbricks/statebus-core'
• StateBus from the old package split into:
  • ManualStateBus in @smoothbricks/statebus-core
  • StateBus (RAF-backed browser implementation) in @smoothbricks/statebus-react