Derived & Readable in Svelte
From the Svelte cheat sheet · Stores · verified Jul 2026
Derived & Readable
Computed and read-only stores
javascript
// stores.js
import { readable, derived } from 'svelte/store';
// Readable store
export const time = readable(new Date(), (set) => {
const interval = setInterval(() => {
set(new Date());
}, 1000);
return () => clearInterval(interval);
});
// Derived store
export const doubled = derived(count, $count => $count * 2);📊 derived() for computed values from stores
🔒 readable() for read-only external data
⚡ Async derived with set callback
🧮 Complex calculations update automatically