如何在填充和查询中使用猫鼬分页

Question

I'm trying use mongoose pagination to process advance search with pagination.

I have the following schemas:

const authorSchema = Schema({
  _id: Schema.Types.ObjectId,
  name: {type: String, unique: true},
});    
const Author = mongoose.model('author', authorSchema, 'author');

const bookSchema = Schema({
_id: Schema.Types.ObjectId,
name: String,
authors:[{type: Schema.Types.ObjectId, ref: 'author'}]
});
const Book= mongoose.model('book', bookSchema , 'book');

I want to find 24 book for page 1 with any book contains author name 'jean'. I do the following with mongoose-paginate module:

 Book.paginate({}, {
    page: 1,
    limit: 24,
    populate: {
     path: 'authors',
     select: 'name',
     match: {
        name: 'jean'
     }
    }, function (err, books) {
        res.json(books);
    });

But the result books contains other book with authors array empty. I cant use books.filter() to remove book with authors. But if i do that, i can't have 24 book per page on result.

What is the right way to do that?

Answer 1

Instead of populate, I suggest to use $lookup in aggregation query.

db.book.aggregate(
{$unwind:'$authors'},
{$lookup:{
    from: 'author',
    localField: 'authors',
    foreignField: '_id',
    as: 'authors'
    }},
    {$unwind: '$authors'},
    {$match: {'authors.name':'Jean'}},
    {$group: {_id: '$_id', authors: {$push: '$authors'}}},
    {$limit: 24}
)