swls-wasm

The Semantic Web Language Server (Turtle, TriG, SPARQL, JSON-LD) compiled to WebAssembly, plus thin helpers for running it as a worker. Built with wasm-pack --target web, so it loads in browsers, bundlers, Web Workers and Node without any bundler plugins.

Both directions exchange whole JSON-RPC messages over postMessage with no Content-Length framing.

Browser / bundler — createSwlsWorker()

The easiest path: get a ready-to-use Web Worker. Works with Vite, webpack, etc. (the bundler picks up the worker and its .wasm automatically).

import { createSwlsWorker } from "swls-wasm/client";

const worker = createSwlsWorker();
// hand `worker` to your editor's LSP client (e.g. swls-codemirror, monaco)

The worker emits { jsonrpc: "2.0", method: "swls/ready" } once the wasm has finished initializing.

From a CDN — no build step

worker.js and its sibling swls_wasm_bg.wasm are both published, so a worker can be loaded straight from a CDN:

const worker = new Worker(
  "https://cdn.jsdelivr.net/npm/[email protected]/worker.js",
  { type: "module" },
);

The worker resolves swls_wasm_bg.wasm relative to its own URL, so it is fetched from the same CDN path. Cross-origin module workers need permissive CORS (jsDelivr and unpkg send it); Safari is stricter about cross-origin worker scripts, so if you need to support it, load a small same-origin bootstrap that import()s the CDN URL.

Custom host — createSwlsServer()

For hosts that aren't a DOM Worker (a Node worker_threads worker, the VS Code web-extension host, …): wire the server to your own transport. post receives each outgoing message (already parsed); feed incoming messages (object or string) into the returned function.

import { createSwlsServer } from "swls-wasm";

const feed = await createSwlsServer((message) => sendToClient(message), {
  debug: (line) => console.log(line),
  // Optional: override how the wasm is loaded. Defaults to fetching the sibling
  // `swls_wasm_bg.wasm`; pass bytes/URL when the host can't fetch that itself
  // (e.g. Node, which can't `fetch` a `file://` URL).
  wasm: undefined,
});

feed({ jsonrpc: "2.0", id: 1, method: "initialize", params: { /* … */ } });

Low-level — WasmLsp

WasmLsp (and the wasm init default export) are also re-exported for full control. createSwlsServer is just a thin wrapper around them.