code: function toLower(obj) {
      const newObj = {};
      _.keys(obj).forEach((key) => {
          const type = typeof (newObj[key.toLowerCase()] = obj[key]);
          if (type === 'object') {
              newObj[key] = toLower(newObj[key]);
          }
      });
      return newObj;
  }
docs: Deep copies JSON object with keys.toLowerCase()
  @param  {Object} obj input
  @return {Object}     output