const fun = (x) => {
  console.log(`Meth... ${x}`);
  setTimeout(() => {
    onReceive(`Fun Received: ${x}`);
  }, 100);
  return x;
}

const publish = () => {
  return new Promise(resolve => {
    window.onReceive = (token) => {
      resolve(token);
    }
  });
}

const Inst = () => {
  const getAs = async(x) => {
    console.log(`Getting As ----- ${x}`);

    const res = await publish(fun(x));

    console.log(`Res is '${res}' ---- ${x}`);
  }

  return {
    getAs,
  }
}

const inst = Object.freeze(Inst());

const a = async() => {
  await inst.getAs(1);
  await inst.getAs(2);
  await inst.getAs(3);
  await inst.getAs(4);
  await inst.getAs(5);
};
a();

const b = async() => {
  await inst.getAs(4);
  await inst.getAs(5);
  await inst.getAs(6);
  await inst.getAs(7);
};
b();
// Comment or remove `b()` to see the different result in Console