mongoose_update_document_version_1.js

app.put('/user/:userId', (req, res) => {
  User.update({ _id: req.params.userId }, $set: req.body.data, (updateFailedError) => {
    if (updateFailedError) {
      res
        .status(500)
        .json({
          errors: [updateFailedError]
        });
    }
    
    res
      .status(204)
      .json({
        success: true
      });
  });
});