Ultimate version solving circular dependency with weakMap

ultimateDeepClone.js

/**
 * Ultimate version solving circular dependency with weakMap
 * Problems:
 * 1. Symbols not covered
 *
 * @param {Object} sourceObj
 * @param {WeakMap} [hash=new WeakMap()]
 * @returns
 */
var deepCloneUltimate = (sourceObj, hash = new WeakMap()) => {
  if (typeof sourceObj !== 'object' && sourceObj !== null) {
    return sourceObj;
  }
  //if we already had the object, we get it
  if (hash.has(sourceObj)) {
    return hash.get(sourceObj);
  }
  let result = Array.isArray(sourceObj) ? [] : {};
  hash.set(sourceObj, result);
  for (let key in sourceObj) {
    if (Object.prototype.hasOwnProperty.call(sourceObj, key)) {
      if (typeof sourceObj[key] !== 'object' && sourceObj[key] !== null) {
        result[key] = deepCloneUltimate(sourceObj[key], hash);
      } else {
        result[key] = sourceObj[key];
      }
    }
  }
  return result;
};