const books = db.group_match_lu_repro_books;
const editions = db.group_match_lu_repro_editions;

books.drop();
editions.drop();

books.insertMany([
    {_id: 0, title: "The C++ Programming Language", edition: "premium"},
    {_id: 1, title: "Programming: Principles and Practice", edition: "premium"},
    {_id: 2, title: "The C Programming Language", edition: "standard"},
    {_id: 3, title: "Object-Oriented Analysis and Design", edition: "standard"},
]);
books.createIndex({edition: 1});

editions.insertMany([
    {edition: "premium", format: "hardcover"},
    {edition: "premium", format: "deluxe"},
    {edition: "standard", format: "paperback"},
    {edition: "standard", format: "ebook"},
]);
editions.createIndex({edition: 1});

const pipeline = [
    {
        $group: {
            _id: "$edition",
            title: {$push: "$title"},
            edition: {$first: "$edition"},
        },
    },
    {$match: {edition: {$in: ["standard", "premium"]}}},
    {
        $lookup: {
            from: editions.getName(),
            localField: "edition",
            foreignField: "edition",
            as: "edition",
        },
    },
    {$unwind: "$edition"},
];

books.explain().aggregate(pipeline);