Errors thrown in async methods are not forwarded correctly

To reproduce:

main.js

import * as Comlink from "https://unpkg.com/comlink/dist/esm/comlink.mjs";
async function init() {
  const worker = new Worker("worker.js");
  const obj = Comlink.wrap(worker);
  try {
    await obj.throwError();
  } catch (err) {
    console.log("Error caught", err);
  }
}
init();

worker.js

importScripts("https://unpkg.com/comlink/dist/umd/comlink.js");

const obj = {
  // THIS IS THE IMPORTANT BIT
  async throwError() {
    throw new Error("foo bar");
  }
};

Comlink.expose(obj);

If you remove async from throwError, the error is caught. Otherwise you get an Uncaught (in promise) error in the console.

[etamponi]

The issues lies at https://github.com/GoogleChromeLabs/comlink/blob/master/src/comlink.ts#L153. I’ve changed it to:

    Promise.resolve(returnValue)
      .catch(err => {
        throwSet.add(err);
        return err;
      })
      .then(returnValue => {

and now it correctly catches errors thrown in async functions.

[hellboywar]

I also encountered this bug today while upgrading to latest comlink, but I can’t wait that long, so I fixed it in PR

@surma thank you for the comlink - it’s a delight to work with

P.S. hope you could publish fixed version sooner!