@octanejs/alien-signals

Alien Signals bindings for Octane. This package ports the public [email protected] API over the unchanged [email protected] core, without React or React types.

Installation

npm install @octanejs/alien-signals
pnpm add @octanejs/alien-signals

import {
  createComputed,
  createSignal,
  useSignal,
  useSignalValue,
} from '@octanejs/alien-signals';

const countSignal = createSignal(1);
const doubledSignal = createComputed(() => countSignal() * 2);

export function Counter() @{
  const [count, setCount] = useSignal(countSignal);
  const doubled = useSignalValue(doubledSignal);

  <button onClick={() => setCount((value) => value + 1)}>
    {'Count: ' + count + ', doubled: ' + doubled}
  </button>
}

The package exports the types ReadableSignal, WritableSignal, SignalSetter, SignalEffectCallback, SignalEffectDependencies, and DependencyList; the core helpers createSignal, createComputed, createEffect, createSignalScope, batch, and trigger; and the hooks useSignal, useSignalValue, useDeferredSignalValue, useSignalSelector, useSetSignal, useSignalEffect, useSignalPassiveEffect, useSignalLayoutEffect, useSignalInsertionEffect, useSignalScope, and useComputed.

A writable signal takes a value. Updater functions are accepted by the setters that useSignal and useSetSignal return, not by the signal itself.

Every component that reads the same signal shares one core subscription. useSignalSelector(signal, selector) re-renders only when the selected value changes by Object.is. useDeferredSignalValue(signal) returns a deferred snapshot of the signal.

useComputed(getter, dependencies) passes its dependency list directly to Octane memoization. Signal dependencies read by getter remain reactive; the explicit list controls when the computed signal itself is rebuilt with a new closure.

useSignalEffect(fn, dependencies?) and useSignalScope(callback, dependencies?) start work after the client commit and dispose it on replacement or unmount. Without a dependency list they restart when the callback identity changes. They do not execute during server rendering. The stop function returned by useSignalScope is stable; it stops the scope that is currently running, and a later dependency change starts a new one.

useSignalPassiveEffect, useSignalLayoutEffect, and useSignalInsertionEffect take a referentially stable list of signals, the effect, and optional extra dependencies. They re-run in the matching effect phase whenever one of those signals changes.

Migrating

Replace imports from react-alien-signals with @octanejs/alien-signals. The hook names and authored call shapes are the same.

Status

Current scope and verification evidence are tracked in the generated bindings status table, sourced from this package's status.json.