What are Svelte stores?

Svelte stores are reactive state containers for sharing state between components. The svelte/store module provides: writable: mutable store: import { writable } from 'svelte/store'; export const count = writable(0);. Update: count.set(5) or count.update(n => n + 1). Subscribe: count.subscribe(value => console.log(value)). readable: immutable from outside — only the store creator can update it. Good for timers, WebSocket connections. derived: computed from one or more stores: const doubled = derived(count, $count => $count * 2). In Svelte components, prefix a store with $ to auto-subscribe and auto-unsubscribe: <p>{$count}</p> — equivalent to subscribing in onMount and unsubscribing in onDestroy.