Web: Change to a webworker architecture to stop freezing main thread

chess-worker.js

@@ -0,0 +1,26 @@
+let exports;
+
+async function init() {
+    const resp = await fetch("./chess.wasm");
+    if (!resp.ok) {
+        throw new Error("fetch wasm failed ${resp.status} ${resp.statusText}");
+    }
+
+    const { instance } =
+        await WebAssembly.instantiateStreaming(resp, {});
+
+    exports = instance.exports;
+}
+await init();
+self.postMessage({ type: "ready" });
+
+self.onmessage = (e) => {
+    const { id, method, args = [] } = e.data;
+    try {
+        const value = exports[method](...args);
+        self.postMessage({ id, ok: true, value });
+    } catch (err) {
+        self.postMessage({ id, ok: false, error: String(err?.message ?? err) });
+    }
+};
+