js-deep-copy-recursion.js

function clone(src) {
  const ret = src instanceof Array ? [] : {};
  for (const key in src) {
    if (!src.hasOwnProperty(key)) {
      continue;
    }
    let val = src[key];
    if (val && typeof val == "object") {
      val = clone(val);
    }
    ret[key] = val;
  }
  return ret;
}

const myObject = {
  hi: "mom",
  changeHi() {
    this.hi = "medium";
  },
  something: undefined,
};

console.log(myObject); // > {hi: "mom", something: undefined, changeHi: ƒ}

const myNewObject = clone(myObject);
myNewObject.changeHi();

console.log(myNewObject); // > {hi: "medium", something: undefined, changeHi: ƒ}