Reject init() promise if webR worker thread fails (#466)

* Reject init promise if webR worker thread fails

* Inline worker error messages

src/tests/webR/error.test.ts

@@ -34,6 +34,23 @@ test('Caught WebRError has the expected error name property', async () => {
  expect(error).toHaveProperty('message', expect.stringContaining('unexpected end of input'));
 });
 
+test('An error is thrown if starting the webR worker fails', async () => {
+ let error: Error | undefined;
+
+ const tempR = new WebR({
+ baseUrl: '../non/existent/path/',
+ });
+
+ await tempR.init().catch((e) => {
+ if (e instanceof WebRError) {
+ error = e;
+ }
+ });
+
+ expect(error).toHaveProperty('name', 'WebRWorkerError');
+ expect(error).toHaveProperty('message', expect.stringContaining('An error occurred'));
+});
+
 afterAll(() => {
  return webR.close();
 });

src/webR/chan/channel-postmessage.ts

@@ -4,7 +4,7 @@ import { Endpoint } from './task-common';
 import { ChannelType } from './channel-common';
 import { WebROptions } from '../webr-main';
 import { ChannelMain } from './channel';
-import { WebRChannelError } from '../error';
+import { WebRChannelError, WebRWorkerError } from '../error';
 
 import { IN_NODE } from '../compat';
 import type { Worker as NodeWorker } from 'worker_threads';
@@ -18,11 +18,14 @@ export class PostMessageChannelMain extends ChannelMain {
 
  initialised: Promise<unknown>;
  resolve: (_?: unknown) => void;
+ reject: (message: string | Error) => void;
  close: () => void = () => { return; };
  #worker?: Worker;
 
  constructor(config: Required<WebROptions>) {
  super();
+ ({ resolve: this.resolve, reject: this.reject, promise: this.initialised } = promiseHandles());
+
  const initWorker = (worker: Worker) => {
  this.#worker = worker;
  this.#handleEventsFromWorker(worker);
@@ -42,8 +45,6 @@ export class PostMessageChannelMain extends ChannelMain {
  const worker = new Worker(`${config.baseUrl}webr-worker.js`);
  initWorker(worker);
  }
-
- ({ resolve: this.resolve, promise: this.initialised } = promiseHandles());
  }
 
  interrupt() {
@@ -55,9 +56,21 @@ export class PostMessageChannelMain extends ChannelMain {
  (worker as unknown as NodeWorker).on('message', (message: Message) => {
  void this.#onMessageFromWorker(worker, message);
  });
+ (worker as unknown as NodeWorker).on('error', (ev: Event) => {
+ console.error(ev);
+ this.reject(new WebRWorkerError(
+ "An error occurred initialising the webR PostMessageChannel worker."
+ ));
+ });
  } else {
  worker.onmessage = (ev: MessageEvent) =>
  this.#onMessageFromWorker(worker, ev.data as Message);
+ worker.onerror = (ev) => {
+ console.error(ev);
+ this.reject(new WebRWorkerError(
+ "An error occurred initialising the webR PostMessageChannel worker."
+ ));
+ };
  }
  }
 

src/webR/chan/channel-service.ts

@@ -11,7 +11,7 @@ import { Endpoint } from './task-common';
 import { ChannelMain, ChannelWorker } from './channel';
 import { ChannelType } from './channel-common';
 import { WebROptions } from '../webr-main';
-import { WebRChannelError } from '../error';
+import { WebRChannelError, WebRWorkerError } from '../error';
 
 import { IN_NODE } from '../compat';
 import type { Worker as NodeWorker } from 'worker_threads';
@@ -25,6 +25,7 @@ export class ServiceWorkerChannelMain extends ChannelMain {
  initialised: Promise<unknown>;
 
  resolve: (_?: unknown) => void;
+ reject: (message: string | Error) => void;
  close = () => { return; };
 
  #syncMessageCache = new Map<string, Message>();
@@ -33,6 +34,8 @@ export class ServiceWorkerChannelMain extends ChannelMain {
 
  constructor(config: Required<WebROptions>) {
  super();
+ ({ resolve: this.resolve, reject: this.reject, promise: this.initialised } = promiseHandles());
+
  console.warn(
  "The ServiceWorker communication channel is deprecated and will be removed in a future version of webR. " +
  "Consider using the PostMessage channel instead. If blocking input is required (for example, `browser()`) " +
@@ -69,8 +72,6 @@ export class ServiceWorkerChannelMain extends ChannelMain {
  const worker = new Worker(`${config.serviceWorkerUrl}webr-worker.js`);
  initWorker(worker);
  }
-
- ({ resolve: this.resolve, promise: this.initialised } = promiseHandles());
  }
 
  activeRegistration(): ServiceWorker {
@@ -154,9 +155,21 @@ export class ServiceWorkerChannelMain extends ChannelMain {
  (worker as unknown as NodeWorker).on('message', (message: Message) => {
  this.#onMessageFromWorker(worker, message);
  });
+ (worker as unknown as NodeWorker).on('error', (ev: Event) => {
+ console.error(ev);
+ this.reject(new WebRWorkerError(
+ "An error occurred initialising the webR ServiceWorkerChannel worker."
+ ));
+ });
  } else {
  worker.onmessage = (ev: MessageEvent) =>
  this.#onMessageFromWorker(worker, ev.data as Message);
+ worker.onerror = (ev) => {
+ console.error(ev);
+ this.reject(new WebRWorkerError(
+ "An error occurred initialising the webR ServiceWorkerChannel worker."
+ ));
+ };
  }
  }
 

src/webR/chan/channel-shared.ts

@@ -5,7 +5,7 @@ import { syncResponse } from './task-main';
 import { ChannelMain, ChannelWorker } from './channel';
 import { ChannelType } from './channel-common';
 import { WebROptions } from '../webr-main';
-import { WebRChannelError } from '../error';
+import { WebRChannelError, WebRWorkerError } from '../error';
 
 import { IN_NODE } from '../compat';
 import type { Worker as NodeWorker } from 'worker_threads';
@@ -20,10 +20,13 @@ export class SharedBufferChannelMain extends ChannelMain {
 
  initialised: Promise<unknown>;
  resolve: (_?: unknown) => void;
+ reject: (message: string | Error) => void;
  close = () => { return; };
 
  constructor(config: Required<WebROptions>) {
  super();
+ ({ resolve: this.resolve, reject: this.reject, promise: this.initialised } = promiseHandles());
+
  const initWorker = (worker: Worker) => {
  this.#handleEventsFromWorker(worker);
  this.close = () => {
@@ -45,8 +48,6 @@ export class SharedBufferChannelMain extends ChannelMain {
  const worker = new Worker(`${config.baseUrl}webr-worker.js`);
  initWorker(worker);
  }
-
- ({ resolve: this.resolve, promise: this.initialised } = promiseHandles());
  }
 
  interrupt() {
@@ -62,9 +63,21 @@ export class SharedBufferChannelMain extends ChannelMain {
  (worker as unknown as NodeWorker).on('message', (message: Message) => {
  void this.#onMessageFromWorker(worker, message);
  });
+ (worker as unknown as NodeWorker).on('error', (ev: Event) => {
+ console.error(ev);
+ this.reject(new WebRWorkerError(
+ "An error occurred initialising the webR SharedBufferChannel worker."
+ ));
+ });
  } else {
  worker.onmessage = (ev: MessageEvent) =>
  this.#onMessageFromWorker(worker, ev.data as Message);
+ worker.onerror = (ev) => {
+ console.error(ev);
+ this.reject(new WebRWorkerError(
+ "An error occurred initialising the webR SharedBufferChannel worker."
+ ));
+ };
  }
  }