Async await

AsyncUser.js

exports.createOrAddUserAsync =  async (req, res, next) => {
  try {
    const user = await User.findUserPromise(req.body);
    if (user) {
      const existingUser = new User(user);
      const data = await existingUser.updatePromise(req.body);
      return res.send(data);
    }

    const newUser = new User();
    const data = await newUser.savePromise(req.body);
    return res.send(data);
  } catch (e) {
    return next(e)
  }
}