@zeus-js/signal

Reactivity core package for Zeus.

Recommended

Zeus applications should use these APIs:

import {
  state,
  computed,
  effect,
  watch,
  scope,
  batch,
  untrack,
  nextTick,
  onCleanup,
} from '@zeus-js/signal'

Export	Description
state	Unified reactive state (primitives, objects, arrays, Map, Set)
computed	Derived reactive value
effect	Reactive side effect
watch	Watcher with callback
scope	Isolated reactive scope
batch	Batch reactive updates
untrack	Read without tracking dependencies
nextTick	Promise-based microtask scheduling
onCleanup	Register cleanup callbacks

state

function state<T>(value: T): T

Unified state API. Works with primitives, objects, arrays, Map, Set.

const count = state(0)
const user = state({ name: 'Zeus' })
const items = state([1, 2, 3])

computed

function computed<T>(fn: () => T): ComputedRef<T>

Creates a derived reactive value.

const doubled = computed(() => count.value * 2)

effect

function effect(fn: () => void): StopFn

Runs fn reactively and tracks its dependencies.

effect(() => {
  console.log('count:', count.value)
})

watch

function watch<T>(
  getter: () => T,
  callback: (newValue: T, oldValue: T) => void,
): void

Watches a reactive value and calls the callback when it changes.

watch(count, (newVal, oldVal) => {
  console.log(`${oldVal} -> ${newVal}`)
})

scope

function scope(): Scope

Creates an isolated reactive scope. Call scope.stop() to dispose all reactive state within.

batch

function batch<T>(fn: () => T): T

Groups reactive updates to avoid redundant effect runs.

untrack

function untrack<T>(fn: () => T): T

Reads reactive values without tracking dependencies.