Partial indexes in mongodb / mongoose

For Mongoid users:

index(
  { user_id: 1, author_id: 1, complete: 1 },
  background: true,
  partial_filter_expression:
    {
      complete: { :$eq => true }
    }
)

Couldn't find any docs, but this PR.

Now it's possible natively with Mongoose +4.6.1

Book.index({user: 1, author: 1, complete: 1}, {unique: true, partialFilterExpression: {complete: true}});

In the current Mongoose version 4.3.7 you cannot define partial indexes in the scheme, but you can still use Partial Indexes of MongoDB 3.2.

You just have to create the indexes using the native driver.

// ScheduleModel is a Mongoose Model
ScheduleModel.collection.createIndex({"type" : 1 } , {background:true , partialFilterExpression : { type :"g" }} , function(err , result){
     console.log(err , result);
});

After that, every query that matches the partialFilterExpression will be indexed.