Simple DFS (if it is plain js object)

dfs.js

const root = {};
const visit = [];
let vn = 0;

function dfs(v) {
    Object.keys(v).forEach(function (k) {
        if (!visit[vn++]) {
            if (typeof(v[k]) === 'object') {
                console.log(k, typeof(k));
                dfs(v[k]);
            }
            else
                console.log(k, v[k]);
        }
        else visit.splice(vn, 0, true);

    });
}

dfs(root);

ES6 version

const visit = {};
let i = 0;

function dfs(v) {
  Object.keys(v).forEach((k) => {
    i++;
    const key = `k${i}`;

    if (!visit[key]) {
      if (typeof(v[k]) === 'object') {
        console.log(k);
        dfs(v[k]);
      } else {
        console.log(k, v[k]);
      }
    } else { 
      visit[key] = true;
    }
  });
}

dfs(root);