The problem with Object.freeze, see more at: https://medium.com/p/1a258c160c07

navigateObjectTree.js

const navigateObj = (obj, level = 0) => {
  const methodsNamesFromFirstLevel = Object.getOwnPropertyNames(obj);

  methodsNamesFromFirstLevel.forEach(prop => {
    console.log(`Prop: ${prop} from level ${level}`);
    if (typeof obj[prop] === "object") {
      navigateObj(obj[prop], ++level);
    }
  });
};

navigateObj({
  obj: {
    with: { a: { lot: "of", different: "levels" }, and: { other: "types" } },
    sub: "structures",
  },
  added: "to",
  a: { long: "navigation" },
});

/*
Will return:

Prop: obj from level 0
Prop: with from level 1
Prop: a from level 2
Prop: lot from level 3
Prop: different from level 3
Prop: and from level 3
Prop: other from level 4
Prop: sub from level 2
Prop: added from level 1
Prop: a from level 1
Prop: long from level 2*/