is mongoose.model() a "CONSTRUCTOR"?

Question

Most of the examples of creating model are like this:

const model = mongoose.model("Collection", schema);

But, if I write:

const model = new mongoose.model("Collection", schema);

That just works fine. I wonder what are the difference between them? Also, which one is the best practice. Moreover, If mongoose.model() is a constructor, how can we use it's instance as a constructor? Like so:

const model = new mongoose.model("Collection", schema); // if 'mongoose.model' a constructor,
const doc = new model({data: data}); // how can we use it's instance as a constructor?
doc.save();