abort-controller-dance.js

class Signal extends EventTarget {
  #aborted = false;
  #controller = null;
  constructor(controller) {
    super();
    this.#controller = controller;
    this.addEventListener('abort', this);
  }
  handleEvent(event) {
    if (event.detail !== this.#controller)
      event.stopImmediatePropagation();
    else
      this.#aborted = true;
  }
  get aborted() {
    return this.#aborted;
  }
}

class Controller {
  constructor() {
    this.signal = new Signal(this);
  }
  abort() {
    this.signal.dispatchEvent(new CustomEvent('abort', {detail: this}));
  }
}

const contr = new Controller;
const {signal} = contr;
signal.addEventListener('abort', console.log);
signal.dispatchEvent(new Event('abort')); // nope
contr.abort();  // yup