spark-html-language-server

spark-html-language-server

Language server (LSP) for Spark single-file .html components. Zero dependencies, speaks LSP over stdio.

What you get

• Diagnostics, live as you type:
  • {binding} used in the template but never declared in <script>
  • JS imports that are never used
  • script syntax errors (the exact code the runtime would execute)
  • <div import="…"> pointing at a component file that doesn't exist
  • each without key= (hint — keyed reconciliation is opt-in)
  • malformed each expressions
• Go-to-definition — jump from <div import="components/card"> to card.html, and from any {symbol} to its let / function / $: / export let declaration.
• Autocomplete
  • props on import placeholders, read from the target component's export let declarations
  • every template directive (each, if/else-if/else, await/then/catch, bind:value|checked|group|form, :hidden-style dynamic attributes, key, route, transition:fade|slide|scale, spark-ignore)
  • script symbols and Spark builtins (useStore, onMount, props) inside {…} and <script>
• Hover docs for every directive and declaration.

Install

bun add -g spark-html-language-server

The spark-html-language-server binary starts the server on stdio — the transport every LSP client speaks.

VS Code

Install the Spark (spark-html) extension from editors/vscode — it bundles syntax highlighting and launches this server automatically (globally installed binary, or node_modules/.bin in your project).

Programmatic use

The analyzer is exported for tooling:

import { analyze } from 'spark-html-language-server';

const { declarations, props, diagnostics } = analyze(componentSource);

Scope (v0.x)

The server analyzes one component at a time — the same boundary the runtime has. It does not type-check across files (props completion reads the target file's export let names, not their types), and remote URL imports are not resolved.

The Spark family

Small, single-purpose packages that share one philosophy: no compiler, no virtual DOM, no build step required. Add only what you use.

Package	What it does
spark-html	The runtime — components, reactivity, stores, forms, scoped styles. 13 kB gzip, 0 deps.
spark-html-bun	Dev server, bundler & preview on Bun — scoped HMR, no-build dev, post-build pipeline.
spark-html-router	<template route> routing — nested routes/layouts, route.query, active links.
spark-html-theme	Dark/light/system theming in one line — persisted, no flash.
spark-html-head	Reactive <title>/<meta> per route + a head store.
spark-html-motion	Enter/leave transitions on if/each blocks — `transition="fade
spark-html-devtools	In-page devtools — live stores, component tree, patch activity.
spark-html-query	Declarative async data — a self-fetching store (loading/error/data/refetch).
spark-html-persist	Persist stores to localStorage/sessionStorage in one line.
spark-html-websocket	A WebSocket as a reactive store — auto-reconnect, JSON, send().
spark-prerender	Build-time SEO prerender + sitemap/robots — no SSR server.
spark-html-image	Build-time image optimization — webp/avif + responsive srcset, zero config.
spark-html-font	Font loading optimizer — preload + size-adjusted fallbacks, no FOUT.
spark-html-manifest	PWA manifest + icons + head tags (and optional service worker) from one config.
spark-html-offline	Offline URL imports — a service worker that caches CDN components.
spark-html-sri	Subresource Integrity — hash + verify assets and remote components.
create-spark-html-app	Scaffold a spark-html app in one command.
prettier-plugin-spark	Prettier for components — formats <script>/<style>, markup stays byte-for-byte.
spark-html-language-server	LSP — diagnostics, go-to-definition, prop autocomplete, hover docs.

License

MIT