@signal-kernel/core

A minimal, deterministic, fine-grained reactivity engine.

Build reactive systems without frameworks — from UI adapters to async dataflow runtimes.

Think of this as a reactive runtime kernel, not a framework.

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 uses a two-phase deterministic scheduler:

1. Recompute all stale computed nodes
2. Execute all effects

→ Guarantees stable and predictable execution order.

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.

Future packages:

• async runtime
• framework adapters

License

MIT © Luciano