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justdom-signal ​

A dependency-tracked reactive library with a pull-based core and an explicit split between the three things a reactive graph does: a Signal is an input, a Derived is a transformation, an Effect is an output. A write computes nothing; it marks what might now be wrong and stops. Values are produced when somebody asks for them, and the asking is what establishes the order.

Installation ​

npm install justdom-signal

rxjs is a peer dependency: any Subscribable can be depended on, and toObservable and fromObservable carry values across the boundary in either direction.

Usage ​

js
import { Signal, Derived, Effect, batch } from "justdom-signal";

const count = Signal.of(0);
const doubled = new Derived(() => count.get() * 2);

// Nothing has been computed yet: nobody has asked.
const effect = new Effect(() => console.log("doubled is now", doubled.get()));
// → "doubled is now 0"

batch(() => {
  count.set(1);
  count.set(2);
});
// → "doubled is now 4", once

effect.dispose();

Learn more ​

  • Reactivity in the guide introduces signals, derived values, effects and channels.
  • The API reference lists every export, its options and defaults: UpdateChannel, store, createProperty, the RxJS interop and the entity layer that justdom-core and justdom-three build on.

License ​

MIT — see LICENSE.

This page is the package's README.