New Twiddle

controllers.application.js

import Ember from 'ember';

class AbortError extends Error {
}
function makeAbortable(promise) {
  const abortController = new AbortController();
  const _promise = promise
  	.then(result => {
      if (abortController.signal.aborted) {
        throw new AbortError;
      } else {
        return result;
      }
    });
  return {
    promise: _promise,
    abort: () => abortController.abort()
  };
}

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  abortDisabled: true,
  
  actions: {
    firePromise() {
      this.set('abortDisabled', false);
      const myPromise = new Ember.RSVP.Promise((resolve, reject) => {
        setTimeout(() => resolve('Hello!'), 2000);
      });
      
      const { promise, abort } = makeAbortable(myPromise);
      promise.then(
          result => alert(result),
          err => {
            if (err instanceof AbortError) {
              alert('Aborted!');
            }
          }
        )
      .finally(() => this.set('abortDisabled', true));
      this.set('abort', abort);
    },
    
    abort() {
      this.get('abort')();
    }
  }
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
<button {{action "firePromise"}}>Fire Promise in 2s</button><br />
<button {{action "abort"}} disabled={{abortDisabled}}>Abort Promise</button>
<br>
<br>

twiddle.json

{
  "version": "0.15.1",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.js",
    "ember": "3.4.3",
    "ember-template-compiler": "3.4.3",
    "ember-testing": "3.4.3"
  },
  "addons": {
    "ember-data": "3.4.2"
  }
}