This is literally what a custom element is. Assuming your @event decorator is built upon the EventTarget interface:

  class MyComponent extends HTMLElement {
    // lifecycle event/method
    connectedCallback() {}
    
    // lifecycle event/method
    disconnectedCallback() {}
    
    @event("mousedown")
    onMouseDown(evt) { }
    
    @event("click", "button#submit")
    onSubmit(evt, button) { }
      
    @event("change", "input.name")
    onNameChange(evt, input) { }
  }

That said, custom elements don't cost $310 for an indie license. Instead, they are free and available in every web browser.