Installation

npm install @signal-kernel/core

Quick Start

import { signal, computed, createEffect } from "@signal-kernel/core";

const count = signal(0);

const doubled = computed(() => count.get() * 2);

createEffect(() => {
  console.log("doubled =", doubled.get());
});

count.set(1);
count.set(2);

Output:

doubled = 2
doubled = 4

What is this?

@signal-kernel/core is a framework-agnostic reactive runtime.

It provides the minimal primitives needed to build reactive systems:

• signal() — mutable state
• computed() — lazy derived values
• createEffect() — reactive side effects
• batch() — update coalescing
• deterministic scheduler

Unlike frameworks (React, Vue), this library:

• does not render UI
• does not manage DOM
• focuses purely on reactive dataflow and execution order

When to use this

Use @signal-kernel/core if you need:

• Fine-grained reactivity (no VDOM diffing)

• Deterministic update ordering

• A foundation for building:

  • UI adapters (React/Vue/Solid)
  • async data pipelines
  • reactive state machines
  • server-side reactive graphs

This is not a UI framework — it is a low-level reactive kernel.

Core Concepts

signal()

const count = signal(0);

count.get();
count.peek();
count.set(1);

computed()

const doubled = computed(() => count.get() * 2);

createEffect()

createEffect(() => {
  console.log(count.get());
});

batch()

batch(() => {
  count.set(1);
  count.set(2);
});

Scheduler Model

This runtime separates synchronous graph invalidation from scheduled side effects:

1. Signal writes mark dependent computed nodes as stale.
2. Effects reached by invalidation are deduplicated and scheduled.
3. Scheduled effects execute in deterministic order.
4. A stale computed value recomputes lazily only when a consumer reads it.

Computed nodes without an active read remain stale and do not perform work. Once recomputed, their values stay cached until another dependency change.

Architecture Overview

For full details, see:

👉 Architecture Documentation

Public API

export { signal } from "./signal.js";
export { computed } from "./computed.js";
export { createEffect, onCleanup } from "./effect.js";
export { batch } from "./scheduler.js";

Design Goals

• Deterministic scheduling
• Lazy computation
• Explicit dependency graph
• Zero framework assumptions
• Adapter-friendly architecture

Ecosystem

@signal-kernel/core is the foundation of the Signal Kernel ecosystem.

Current companion packages:

• @signal-kernel/async-runtime
• @signal-kernel/react
• @signal-kernel/vue

Planned companion packages:

• snapshot and transfer packages

License

MIT © Luciano