Signals

A signal is the unit of reactive state. createSignal returns a getter/setter pair:

import { createSignal } from '@fluixi/reactive/signal';

const [count, setCount] = createSignal(0);

count();        // read  → 0
setCount(1);    // write → 1
setCount(c => c + 1); // update from the previous value → 2

Reading is tracking

Calling the getter inside a memo or effect subscribes that computation to the signal. The next write re-runs only the computations that read it:

createEffect(() => {
  console.log('count is', count()); // subscribes to count
});
setCount(5); // logs "count is 5"

Reading outside any reactive scope just returns the value — no subscription.

Equality

By default a signal skips notifying readers when the new value is === the old one. Pass equals to customize, or equals: false to always notify:

const [list, setList] = createSignal([], { equals: false });

Reading without subscribing

Use untrack to read a signal without creating a dependency:

import { untrack } from '@fluixi/reactive/signal';

createEffect(() => {
  draw(count(), untrack(theme)); // re-runs on count, but not on theme
});

Next: Derived values.