@pyreon/reactivity

Signal-based fine-grained reactivity primitives for the Pyreon framework.

Install

bun add @pyreon/reactivity

Quick Start

import { signal, computed, effect, batch } from '@pyreon/reactivity'

const count = signal(0)
const doubled = computed(() => count() * 2)

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

batch(() => {
  count.set(1)
  count.set(2)
})
// logs "doubled: 4" once

API

Signals

• signal<T>(initial: T, options?): Signal<T> -- Callable getter with .set(value) and .update(fn) methods. Pass { name } for debug labels (auto-injected by @pyreon/vite-plugin in dev mode).
• computed<T>(fn, options?): Computed<T> -- Derived signal that recomputes lazily when dependencies change.
• cell<T>(initial: T): Cell<T> -- Lightweight reactive cell.

Effects

• effect(fn): Effect -- Runs fn and re-runs it whenever its tracked dependencies change.
• onCleanup(fn) -- Registers a cleanup function inside an effect. Runs before re-execution and on disposal.
• renderEffect(fn): Effect -- Like effect, but scheduled for render timing.
• watch(source, callback, options?): WatchOptions -- Watches a reactive source and calls back on change.
• setErrorHandler(handler) -- Sets a global error handler for effect errors.

Batching

• batch(fn) -- Groups multiple signal writes; subscribers notified once at the end.
• nextTick(): Promise<void> -- Resolves after the current batch of updates flushes.

Tracking

• runUntracked(fn) -- Runs fn without tracking any signal reads.
• untrack(fn) -- Alias for runUntracked.

Scopes

• effectScope(): EffectScope -- Creates a scope that collects effects for bulk disposal.
• getCurrentScope(): EffectScope | undefined -- Returns the active effect scope.
• setCurrentScope(scope) -- Manually sets the current effect scope.

Selectors and Resources

• createSelector(source) -- Creates an efficient selector for keyed comparisons.
• createResource(fetcher): Resource<T> -- Wraps an async data source in a reactive resource.

Stores

• createStore(initial) -- Creates a deeply reactive store object.
• isStore(value): boolean -- Checks whether a value is a reactive store.
• reconcile(target, source) -- Efficiently patches a store to match a new value.

License

MIT