How do I remove an array of referenced Objects when deleting the main document?

Question

This is my MongoDB schema:

const MenuSchema = new Schema({
  name: {
    type: String,
    require: true
  },
  category: {
    type: String,
    require: true
  },
  description: {
    type: String,
    require: true
  },
  image: {
    type: String,
  },
  caterer: {
    type: Schema.Types.ObjectId,
    ref: 'User'
  },
  products: [{
    type: Schema.Types.ObjectId,
    ref: 'Product'
  }]
}, { timestamps: true })


const ProductSchema = new Schema({
  name: {
    type: String,
    require: true
  },
  category: {
    type: String,
    require: true
  },
  description: {
    type: String,
    require: true
  },
  image: {
    type: String,
  },
  price: {
    type: String
  }
}, { timestamps: true })

What I'm wondering - is how I can delete the array of products, at the same time as I delete the main "Menu" document? When I remove the Menu, I can also assume that the products belonging to the menu should be removed.

At the moment this is how I remove the menu (and tried to remove its products):

await Menu.findOneAndDelete({ _id: req.params.menu_id }, (err, response) => {
      if (err) {
        console.error(err);
      }
      Product.remove({ _id: { $in: req.body.products }}, (err, res) => {
        if (err) {
          console.error(err);
        }
        console.log('Deleted products');
      });
    });

However, the products do not get removed. Any suggestions?

Answer 1

Mongoose provides a pre and post middleware on your schema. Which means you can delete all the referenced documents before or after you do an operation on the current schema.

Read more here.

Here's an example, inside your schema add this:

const MenuSchema = new Schema({
  name: {
    type: String,
    require: true
  },
  category: {
    type: String,
    require: true
  },
  description: {
    type: String,
    require: true
  },
  image: {
    type: String,
  },
  caterer: {
    type: Schema.Types.ObjectId,
    ref: 'User'
  },
  products: [{
    type: Schema.Types.ObjectId,
    ref: 'Product'
  }]
}, { timestamps: true })


const ProductSchema = new Schema({
  name: {
    type: String,
    require: true
  },
  category: {
    type: String,
    require: true
  },
  description: {
    type: String,
    require: true
  },
  image: {
    type: String,
  },
  price: {
    type: String
  }
}, { timestamps: true })


MenuSchema.post('remove', removeProducts);

function removeProducts(doc) {
   Products.remove({_id: { $in: doc.products}})
}

Assuming Products is the name of your model.