Model.create retrive how many documents have been created

Question

Model.create retrive how many documents have been created

I am using Model.create(Array) in Mongoose.
I want to provide user a feedback about how many documents have been created and how many of them haven't (i.e. they didn't validate).
I created a callback like this

User.create(usersToImport, function(err, docs) {  
    console.log(err);
    console.log(docs);
}

The problem is that if any document does not validate, I only receive a validation error on the single non-valid document, while I cannot retrieve any information about the inserted documents.
Is there any way to get this information?

node.js
mongodb
validation
mongoose
bulkinsert

Answer 1

I think, you need something like .settle() method from when.js module.

Here is an example of doing it using when.js with mongoose 3.8.x:

when = require('when');

promises = usersToImport.map(function(user) {
  return User.create(user); // returns Promise
});
when.settle(promises).then(function(results) {
  // results is an array, containing following elements:
  //   { state: 'fulfilled', value: <document> }
  //   { state: 'rejected', value: <error> }
});

It's possible to do it without Promises (e.g. using async module), but the code will be much more complicated.

Answer 2

Model.create() isn't going to return that information for you. The best option would be to roll your own version of Model.create(), which is essentially a convenience method for calling Model.save() multiple times, and collate the information yourself. A good way to get started is the code for Model.create().