@vobs/reactivity

The signals engine of the vobs framework: state, memo, effect, scheduler, and the owner tree that manages disposal.

Pull-based evaluation with push-invalidation: writes mark dependents dirty instead of eagerly recomputing, a microtask flush runs only dirty nodes (deduplicated), and loops are detected and thrown after a bounded number of rounds.

Install

npm install @vobs/reactivity

Framework-free — usable without the vobs renderer.

Quick start

import { state, memo, effect } from '@vobs/reactivity'

const count = state(0)
const doubled = memo(() => count.value * 2)

effect(() => console.log(doubled.value)) // logs 0
count.value = 2                          // logs 4 (batched into a microtask flush)

Ownership and disposal

Every effect, memo, and signal created inside an owner is disposed with it:

import { createOwner, effect, onDispose } from '@vobs/reactivity'

const owner = createOwner()

owner.run(() => {
  effect(() => trackSomething())
  onDispose(() => console.log('cleanup'))
})

owner.dispose() // runs 'cleanup', disposes the effect

Batching

import { batch, state } from '@vobs/reactivity'

batch(() => {
  first.value = 'a'
  last.value = 'b'   // observers run once, after both writes
})

API

| Signature | Description | | --- | --- | | state(value) | Creates a writable signal. Read/write via .value; subscribes the current effect/memo on read. | | memo(fn) | Cached derivation; recomputes only when dependencies change and the value is read after invalidation. | | effect(fn) | Runs fn immediately, then re-runs on dependency changes. Auto-disposed by the current owner. renderEffect is a render-side alias. | | untrack(fn) | Reads signals without subscribing. | | batch(fn) | Defers flushes until fn returns. | | scheduleLow(fn) | Schedules work at lower scheduler priority. | | scheduler | Flush scheduler with priority lanes and cycle detection. | | createOwner() / getCurrentOwner() / runWithOwner(owner, fn) | Owner tree primitives for scoped lifecycle. | | onDispose(cleanup) | Registers cleanup on the current owner (throws outside an owner). | | setOwnerDebugName(owner, name) / getOwnerDebugName(owner) | Names for devtools inspection. | | useId(prefix?) / createId() | SSR-stable unique ids. |

Types

Signal<T>, Memo<T>, Effect, Owner, Scheduler, Dependency, Subscriber.