Add an SqliteWorker

src/workers/sqlite.worker.ts

@@ -0,0 +1,32 @@
+/// <reference lib="webworker" />
+
+import { DenoSqlite3 } from '@/deps.ts';
+
+let db: DenoSqlite3;
+
+type Msg =
+  | ['open', [string]]
+  | ['query', [string, unknown[]]];
+
+function call([cmd, args]: Msg) {
+  switch(cmd) {
+    case 'open':
+      return handleOpen(args[0]);
+    case 'query':
+      return handleQuery(args[0], args[1]);
+  }
+}
+
+function handleOpen(path: string): void {
+  db = new DenoSqlite3(path);
+}
+
+function handleQuery(sql: string, params: any[] = []) {
+  return db.prepare(sql).all(...params);
+}
+
+self.addEventListener('message', (event: MessageEvent<[string, Msg]>) => {
+  const [id, msg] = event.data;
+  const result = call(msg);
+  self.postMessage([id, result]);
+});