coaction

An efficient and flexible state management library for building high-performance, multithreading web applications.

Coaction 2.0 uses alien-signals internally for cached getter/computed state, React selector reactivity, and adapter-facing subscriptions. The core package also re-exports the signal primitives for advanced integrations.

Installation

You can install it via npm, yarn or pnpm.

npm install coaction

Usage

import { create } from 'coaction';

const store = create((set) => ({
  count: 0,
  get doubleCount() {
    return this.count * 2;
  },
  increment() {
    set(() => {
      this.count += 1;
    });
  }
}));

Accessor getters are cached automatically through the built-in signal runtime. Use get(deps, selector) when you want to declare dependencies manually:

const store = create((set, get) => ({
  count: 0,
  doubleCount: get(
    (state) => [state.count],
    (count) => count * 2
  ),
  increment() {
    set(() => {
      this.count += 1;
    });
  }
}));

Advanced integrations can import the native signal primitives and adapter helper directly from coaction:

import { computed, defineExternalStoreAdapter, effect, signal } from 'coaction';

Store methods using this are rebound to the latest state when invoked from getState(), so destructuring remains safe:

const store = create((set) => ({
  count: 0,
  increment() {
    set(() => {
      this.count += 1;
    });
  }
}));

const { increment } = store.getState();
increment();

API Reference

• Generated core API index
• Core API notes

Store Shape Mode (sliceMode)

create() uses sliceMode: 'auto' by default. For backward compatibility, auto still treats a non-empty object whose enumerable values are all functions as slices. That shape is ambiguous with a plain store that only contains methods, so development builds warn and you should set sliceMode explicitly.

You can force behavior explicitly:

• sliceMode: 'single': treat object input as a single store.
• sliceMode: 'slices': require object-of-slice-functions input.

create({ ping: () => 'pong' }, { sliceMode: 'single' });
create({ counter: (set) => ({ count: 0 }) }, { sliceMode: 'slices' });

Documentation

You can find the documentation here.