jsonTree.js

const _ = require('lodash');

function printKeys(key, obj, parentKeyPath = '') {
  const keyPath = `${parentKeyPath}.${key}`;
  console.log(keyPath);

  if (_.isArray(obj) && !_.isEmpty(obj)) {
    printKeys(key, _.head(obj), keyPath);
  } else if (_.isObject(obj)) {
    const firstKey = _.head(_.keys(obj));
    if (_.toNumber(firstKey).toString() === firstKey.toString()) {
      const firstObj = obj[firstKey];
      printKeys(firstKey, firstObj, keyPath);
    } else {
      _.map(obj, (newObj, newKey) => printKeys(newKey, newObj, keyPath));
    }
  }
}

let content = '';
process.stdin.resume();
process.stdin.on('data', (buf) => {
  content += buf.toString();
});
process.stdin.on('end', () => {
  const json = JSON.parse(content);
  printKeys('ROOT', json, '', 0);
});