Svelte — Compile-Time Reactive UI Framework

Overview

Svelte shifts work from runtime to compile time, producing minimal vanilla JavaScript with no virtual DOM. Svelte 5 introduces runes — explicit reactivity primitives that replace $: declarations and stores. SvelteKit 2 provides SSR, routing, and deployment adapters.

Instructions

Runes Reference

$state — reactive state (deep by default):

<script lang="ts">
  let count = $state(0);
  let user = $state({ name: "Alice", age: 30 });
  user.age++;  // deep reactivity — triggers updates
</script>