createSharedComposable#

Reference-counted sharing of an effect-ful composable: the first subscriber runs it in a fresh detached effectScope; later subscribers get the same result. Cross-platform — import from @sigx/use.

TypeScript 
import { createSharedComposable } from '@sigx/use';
import { useMouse } from '@sigx/use-web';

export const useSharedMouse = createSharedComposable(useMouse);

// in any number of components — ONE mousemove listener total:
const mouse = useSharedMouse();

This is the standard way to turn a per-caller sensor into an app singleton — N components share ONE mousemove listener (see useMouse). When the last subscriber's scope disposes, the shared scope stops (listeners detach, timers clear) and the next call re-creates everything.

Refcount semantics#

Subscribers are counted per in-scope call — each call registers a matching dispose with its owning scope. Calling twice in one scope counts twice, and both disposers fire together when that scope stops.

Calls made outside any component or effectScope don't participate in refcounting: they receive (and, when first, create) the shared state without incrementing the count. So a shared instance created by an out-of-scope call lives until a later scoped subscriber's dispose brings the count back to zero. Prefer calling from a scope (a component setup, or wrap standalone use in effectScope()).

Signature#

TypeScript 
function createSharedComposable<Fn extends (...args: never[]) => unknown>(composable: Fn): Fn;

The returned function has the same signature as the composable you pass.

Platform: everywhere.

See also#

  • createGlobalState — a never-disposed singleton for plain state factories (no refcounting).
  • useMouse — the canonical sensor to share this way.
  • @sigx/store — defineStore for structured, per-user application state.