Deep object clone without functional properties

structuralClone.js

function structuralClone(obj) {
  return new Promise(resolve => {
    const {port1, port2} = new MessageChannel();
    port2.onmessage = ev => resolve(ev.data);
    port1.postMessage(obj);
  });
}

var obj = {a: 1, b: {
    c: b
}}
// pay attention that this method is asynchronous
// it can handle `undefined` and circular reference object
const clone = await structuralClone(obj);