deepcopy.js

function isObject(obj) {
  var type = typeof obj;
  return (type === 'function' || type === 'object') && !!obj; // this will handle obj , null and undefined
};

function deepClone(src) {
  let target = {};
  let keys = Object.keys(src);
  for (let i = 0, len = keys.length; i < len; i++ ) {
    let key = keys[i];
    if (src.hasOwnProperty(key)) {
      // if the value is a referece(object), recursively copy all properties by calling deepClone
      let val = src[key];
      let isObj = isObject(val);
      if (isObj) {
        target[key] = deepClone(val);
      } else {
        target[key] = val;
      }
    }
  }
  return target;
}