Hooks

Kosame provides hooks that are called before CRUD operations are executed and allow you to abort a write operation by throwing an exception.

How to Use Hooks

beforeCreate()

You use beforeCreate() by overriding it in the Model class. It is automatically called before context.<collection>.add() is executed, and you can prevent the write operation by throwing an exception.

override async beforeCreate() {
  if (!this.name.includes("kosame")) {
    throw new Error("Name must contain kosame");
  }
}

By the time beforeCreate() is called, this.name already contains the value to be inserted. In this code example, an exception is thrown to stop the write operation if the name does not contain kosame.

beforeUpdate(changes)

You use beforeUpdate() by overriding it in the Model class. It is automatically called before the instance's update() method is executed, and you can prevent the write operation by throwing an exception. Since changes is passed by reference, any changes made within the hook will be reflected directly in the database write.

beforeDelete()

You use beforeDelete() by overriding it in the Model class. It is automatically called before the instance's delete() method is executed, and you can prevent the write operation by throwing an exception.