feat: get web worker mechanism working (pass file around)

src/util/WorkerEventBus.ts

@@ -0,0 +1,62 @@
+import { nanoid } from 'nanoid';
+
+export class WorkerClientBus {
+  private idPromiseMap = new Map<string, [(data: any) => void, (error: Error) => void]>();
+
+  constructor(private worker: Worker) {
+    worker.addEventListener('message', (e) => {
+      const { id, result, error } = e.data;
+      const actionPromise = this.idPromiseMap.get(id);
+      if (!actionPromise) {
+        console.error('cound not fetch worker promise for action: %s', id);
+        return;
+      }
+      this.idPromiseMap.delete(id);
+
+      const [resolve, reject] = actionPromise;
+      if (error) {
+        reject(error);
+      } else {
+        resolve(result);
+      }
+    });
+  }
+
+  async request<R = any, P = any>(actionName: string, payload: P): Promise<R> {
+    return new Promise((resolve, reject) => {
+      const id = nanoid();
+      this.idPromiseMap.set(id, [resolve, reject]);
+      this.worker.postMessage({
+        id,
+        action: actionName,
+        payload,
+      });
+    });
+  }
+}
+
+export class WorkerServerBus {
+  private handlers = new Map<string, (payload: any) => Promise<any>>();
+
+  addEventHandler<R = any, P = any>(actionName: string, handler: (payload: P) => Promise<R>) {
+    this.handlers.set(actionName, handler);
+  }
+
+  onmessage = async (e: MessageEvent<any>) => {
+    const { id, action, payload } = e.data;
+    const handler = this.handlers.get(action);
+    if (!handler) {
+      postMessage({ id, result: null, error: new Error('Handler missing for action ' + action) });
+      return;
+    }
+
+    let result = undefined;
+    let error = undefined;
+    try {
+      result = await handler(payload);
+    } catch (e: unknown) {
+      error = e;
+    }
+    postMessage({ id, result, error });
+  };
+}