Minimal AbortController implementation for node.js that doesn't have to shim DOM stuff

AbortController.ts

import { EventEmitter } from 'events';

class AbortSignal {
  private events = new EventEmitter();

  constructor(
    private getIsAborted: () => boolean
  ) {}

  get aborted(): boolean {
    return this.getIsAborted();
  }

  addEventListener(event: 'abort', fn: () => void) {
    this.events.once(event, fn);
  }

  removeEventListener(event: 'abort', fn: () => void) {
    this.events.removeListener(event, fn);
  }
}

class AbortController {
  private events = new EventEmitter();
  private isAborted = false;
  readonly signal: AbortSignal;

  constructor() {
    this.signal = new AbortSignal(() => this.isAborted)
  }

  abort() {
    if (!this.isAborted) {
      this.isAborted = true;
      this.events.emit('abort');
    }
  }
}