@serve-tools/signal-effect

The @serve-tools/signal-effect package provides microtask-batched effects for TC39 Signals, built on @serve-tools/signal.

import { Signal } from "@serve-tools/signal";
import { effect } from "@serve-tools/signal-effect";

const value = new Signal.State("initial");
const dispose = effect(() => console.log(value.get()));

value.set("updated");

dispose();

Install

npm install @serve-tools/signal @serve-tools/signal-effect

Effect depends on @serve-tools/signal. Applications that import Signal directly should also declare it so package managers can share one compatible installation.

Effects run synchronously once, then batch subsequent invalidations onto the next microtask. createEffect provides a dormant controller for consumers that must register disposal before the initial run.

import { createEffect } from "@serve-tools/signal-effect";

const controller = createEffect(() => console.log(value.get()));

addEventListener("pagehide", controller.dispose, { once: true });
controller.start();

Disposal is idempotent and skips an effect that was already pending. If an initial run throws, its controller disposes itself before rethrowing. During a batch, later effects still run after an earlier failure; multiple failures are combined in an AggregateError.

Public API

• effect(run) executes immediately, tracks the signals read by run, and returns an idempotent disposer.
• createEffect(run) returns a dormant Effect controller with start() and dispose().
• Effect describes the dormant controller, and Dispose describes an effect disposer.

Compatibility

The package is an ES module for JavaScript runtimes with queueMicrotask and a compatible @serve-tools/signal installation. It does not install global APIs.

Agent Skill

This package includes skills/serve-tools-signal-effect/SKILL.md with version-aligned usage guidance for compatible coding agents. Activation is explicit; installing the package does not automatically trust or enable it.

Development

The default test command runs the scheduler suite in Node.js, Chromium, Firefox, and WebKit.

npm test --workspace @serve-tools/signal-effect

Run the opt-in scheduler and fanout benchmarks with:

npm run benchmark --workspace @serve-tools/signal-effect

License

MIT-0