Check if key exists in both document and subdocument and append

I have a book schema where each book can belong in a category and subcategory. If a category doesn't exist I create it, if the subcategory doesn't exist I create it. I'm having trouble figuring out the syntax to create the subdirectory once the category is created.

var BookSchema = new Schema({
category : {
    name: String,
    list: [{
        subcategory: {
            name: String,
            list: [{
                books: {
                    title: String
                }
            }]
        }
    }]
}
});

What I have so far

Book.findOne({"category.list.subcategory.name": subcategory}, function(err, subcategory) {

            if (err) {
                console.log("MongoDB Error: " + err);
                return false; // or callback
            }
            if (!subcategory) {
                console.log("No item found, creating subcategory item");

                Book.create(
                    {
                        'category.list.subcategory.name': subcategory
                    }, function(err, createdSubcategory) {
                        if (err) {
                            console.log("Create Subcategory MongoDB Error: " + err);
                            return null; // or callback
                        }
                        console.log(createdSubcategory)
                    }
                );
            }
            else {
                console.log("Found subcategory item: " + tracksTableItem.for_user);
                //Add or update subcategory

            }
            console.log('-wattttttt-------')
            return true; // or callback
        });

Except this isn't working, I think because I'm not finding the category to create the subcategory under

via testinggnitset ser