Web Workers handling in wasm build.

[ebala96]

I have a web worker code piece in my project.
It works fine when I do a flutter run web or take a web build.

But when I try to do a flutter run web --wasm or flutter build web --wasm, the web worker part does not work.
I am not able to do postMessage to my web worker instance.

Code snippet for creating and sending messages to web worker:

import 'dart:async';
import 'dart:js_interop';
import 'dart:typed_data';
import 'package:web/web.dart' as web;

class WebWorkers {

  final _workers = <int, web.Worker>{};

  Future<int> create(String url) async{
    print('WebWorkersWeb.create: $url');
    final worker = web.Worker(url.toJS);
    final id = _workers.length;
    _workers[id] = worker;
    return id;
  }
  
   Stream<String> onMessage(int id) {
      print('WebWorkersWeb.onMessage: $id');
      final worker = _workers[id];
  
      if (worker == null) {
        throw PlatformException(
          code: 'Unimplemented',
          details: 'web_worker for web doesn\'t implement \'${id}\'',
        );
      }
  
      final controller = StreamController<String>();
      worker.addEventListener('message', (web.MessageEvent msg){
        print('message from worker is ${msg.data.toString()}');
        controller.add(msg.data.toString());
      }.toJS);
  
      return controller.stream;
   }
    
   Future<void> postMessage(int id, String message) async{
      print('WebWorkersWeb.postMessage: $id, $message');
      final worker = _workers[id];
  
      worker.postMessage(message.toJS);
   }

}

Does web worker in wasm builds require any additional handling?

[srujzs]

Can you share a minimal repro and the error you are seeing here? The above example doesn't have a main method. There shouldn't be any additional handling for web workers when compiling to Wasm.