Adding more models

server/models/BookTag.js

@@ -0,0 +1,31 @@
+const { DataTypes, Model } = require('sequelize')
+
+module.exports = (sequelize) => {
+  class BookTag extends Model { }
+
+  BookTag.init({
+    id: {
+      type: DataTypes.UUID,
+      defaultValue: DataTypes.UUIDV4,
+      primaryKey: true
+    }
+  }, {
+    sequelize,
+    modelName: 'BookTag',
+    timestamps: false
+  })
+
+  // Super Many-to-Many
+  // ref: https://sequelize.org/docs/v6/advanced-association-concepts/advanced-many-to-many/#the-best-of-both-worlds-the-super-many-to-many-relationship
+  const { Book, Tag } = sequelize.models
+  Book.belongsToMany(Tag, { through: BookTag })
+  Tag.belongsToMany(Book, { through: BookTag })
+
+  Book.hasMany(BookTag)
+  BookTag.belongsTo(Book)
+
+  Tag.hasMany(BookTag)
+  BookTag.belongsTo(Tag)
+
+  return BookTag
+}