Examples

Persisting State with Local Storage

Save and restore atom values using the browser’s local storage.

import { atom } from '@reaxium/core';
import { LocalStorageSystem } from '@reaxium/core';

const counter = atom(0, LocalStorageSystem('counter'));
counter.set(1);
// Value is automatically saved to localStorage

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Derived State with Computed

Create a computed value that depends on multiple atoms.

import { atom, computed } from '@reaxium/core';

const width = atom(10);
const height = atom(20);
const area = computed(
  () => width.get() * height.get(),
  [width, height]
);

console.log(area.get()); // 200
width.set(5);
console.log(area.get()); // 100

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Subscribing to Changes

React to state changes with subscriptions.

import { atom } from '@reaxium/core';

const user = atom({ name: 'Alice' });
const unsubscribe = user.subscribe((value) => {
  console.log('User changed:', value);
});
user.set({ name: 'Bob' });
// Logs: "User changed: { name: 'Bob' }"
unsubscribe(); // Stop listening