mongoose - How to group by foreign and make foreign key doc field as root in mongodb

Question

I have two models mmmenu(MainMenu) and MenuSchema(like subMenu)

const mainMenuSchema = new mongoose.Schema({
  title: {
    type: String,
    required: [true, "Please provide main menu title"],
    unique: true,
  },
  res_id: {
    type: mongoose.Types.ObjectId,
    ref: "resturant",
    required: [true, "Please provide res_id"],
  },
});
//SubMenu model
  const MenuSchema = new mongoose.Schema({
  title: {
    type: String,
    required: [true, "Please provide  menu title"],
    unique: true,
  },
  price: {
    type: Number,
    required: [true, "Please provide  price"],
  },
  image_url: {
    type: String,
    required: [true, "Please provide  image_url"],
  },
  mmenu: {
    type: mongoose.Types.ObjectId,
    ref: "mmenu",
    required: [true, "Please provide   mmenu"],
  },
  res_id: {
    type: mongoose.Types.ObjectId,
    ref: "resturant",
    required: [true, "Please provide res_id"],
  },
});

I am querying from submenuModel but i want to group by mmenu and field should have title as key and populated doc as value ?

Answer 1

等待大神答复