Polymorphic State Evaluation via Abstract Handler Inheritance in Svelte Action Directives

class BaseInteractionHandler {
  constructor(node) {
    this.node = node;
  }
  handleEvent(event) {
    throw new Error('Abstract method handleEvent must be overridden');
  }
  destroy() {}
}
 
class HoverInteractionHandler extends BaseInteractionHandler {
  constructor(node) {
    super(node);
    this.onPointerEnter = (e) => this.handleEvent(e);
    this.node.addEventListener('pointerenter', this.onPointerEnter);
  }
  handleEvent(event) {
    this.node.dataset.hovered = 'true';
  }
  destroy() {
    this.node.removeEventListener('pointerenter', this.onPointerEnter);
  }
}
 
export function polymorphicAction(node, HandlerClass = HoverInteractionHandler) {
  const instance = new HandlerClass(node);
  return {
    destroy() {
      instance.destroy();
    }
  };
}