Can't get external async function to work

[BoryaGames]

This code:

var { Arena } = require("quickjs-emscripten-sync");
var ctx = (await QJS.getQuickJS()).newContext();
var arena = new Arena(ctx, {
  "isMarshalable": true
});
arena.expose({
  console
});
arena.evalCode(`
  (async () => {
    console.log(1);
    await new Promise(res => res("cat"));
    console.log(2);
  })();
`);

It prints 1 and after I do arena.executePendingJobs();, it works printing 2.
However, I can't get an external Promise to work.

var { Arena } = require("quickjs-emscripten-sync");
var ctx = (await QJS.getQuickJS()).newContext();
var arena = new Arena(ctx, {
  "isMarshalable": true
});
function someAsyncOperation() {
  return new Promise(resolve => {
    setTimeout(() => {
      resolve("cat");
    }, 1000);
  });
}
arena.expose({
  console, someAsyncOperation
});
arena.evalCode(`
  (async () => {
    console.log(1);
    await someAsyncOperation();
    console.log(2);
  })();
`);

It prints 1 and fails with Method Promise.prototype.then called on incompatible receiver #<Promise>
Am I'm doing something wrong?

[BoryaGames]

I got this to work by making a custom marshaller:

      this.#arena = new Arena(this.#ctx, {
        "isMarshalable": true,
        "customMarshaller": [(target, ctx) => {
          if (target instanceof Promise) {
            var promise = ctx.newPromise();
            var options = {
              ctx,
              "unmarshal": this.#arena._unmarshal,
              "isMarshalable": this.#arena._isMarshalable,
              "find": this.#arena._marshalFind,
              "pre": this.#arena._marshalPre,
              "preApply": this.#arena._marshalPreApply,
              "custom": this.#arena._options?.customMarshaller
            };
            target.then(d => {
              return promise.resolve(marshal(d, options));
            }, d => {
              return promise.reject(marshal(d, options));
            });
            return promise;
          }
        }]
      });

I do not understand why it works like this, as the code is identical to the original one...
And now I get Class constructors cannot be invoked without 'new'
Seems if (new.target) { in this library doesn't work

[BoryaGames]

After some debugging, I found out why custom marshaller worked - I'm running NW.js which has two mixed contents with QuickJS inside browser one and this QuickJS-sync inside nodejs one, so they had some issues.
Now Promises do actually work with no custom marshallers needed!
I still have problems with classes, though.

[rot1024]

Triaged: Per your follow-up comments, the Promise / external async function case now works without a custom marshaller (the original problem turned out to be the mixed NW.js browser/node QuickJS contexts). The remaining Class constructors cannot be invoked without 'new' problem is a separate concern — could you open a dedicated issue for the class/new.target case with a minimal repro? Closing this one as resolved.