试图通过猫鼬查询取消诺言

Question

I currently have a create method that creates a new adventure, saves it, then adds the resulting adventure's ID to a user. The only problem is, it has nested promises and I'm wondering if there's a way to prevent that. The code:

function create(req, res) {
  new Adventure(req.body)
    .save()
    .then(function (result) {
      User.findByIdAndUpdate(
        result.dm_id,
        { $push: { adventures: result._id }}
      )
        .exec()
        .catch(fail); // FIXME: nested promises :(
      res.status(200).send(result);
    })
    .catch(fail);
}

I think the catch here is that I need to send the response back with the adventure I created, rather than the user I add the adventure to.

Thanks!

Answer 1

If you return the promise that (your code implies) is returned by .exec - then you should be able to do something like this

function create(req, res) {
    new Adventure(req.body)
    .save()
    .then(function (result) {
        var ret = User.findByIdAndUpdate(result.dm_id, { $push: { adventures: result._id }}).exec();
        res.status(200).send(result);
        return ret;
    })
    .catch(fail);
}

or

function create(req, res) {
    new Adventure(req.body)
    .save()
    .then(function (result) {
        res.status(200).send(result);
        return User.findByIdAndUpdate(result.dm_id, { $push: { adventures: result._id }}).exec();
    })
    .catch(fail);
}

not sure if it's "valid" to use res.status line before the findByIdAndUpdate line, so this second code block may be wrong