Cancelling a Task from a Child Component

components.child-component.js

import Ember from 'ember';
import { task } from 'ember-concurrency';

export default Ember.Component.extend({
  childTask: task(function*() {
    yield this.performParentTask()
  })
});

components.parent-component.js

import Ember from 'ember';
import { task, timeout } from 'ember-concurrency';

export default Ember.Component.extend({
  childComponentIsMounted: true,
  
  parentTask: task(function*() {
    try {
      yield timeout(1000);
    
      window.alert('Finished Successfully!');
    } catch(e) {
      window.alert('Task was cancelled because the child was un-mounted!')
    }
  }),
  
  actions: {
    toggleChild() {
      this.set('childComponentIsMounted', !this.get('childComponentIsMounted'));
    }
  }
});

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle'
});

templates.application.hbs

<ParentComponent />

templates.components.child-component.hbs

<button {{action (perform childTask)}}>
  Run task in the child!
</button>

templates.components.parent-component.hbs

<button {{action 'toggleChild'}}>
  Toggle Child Component
</button>
  
<hr />

{{#if this.childComponentIsMounted}}
  <ChildComponent @performParentTask={{perform this.parentTask}} />
{{/if}}

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",
    "ember-concurrency": "1.1.2"
  }
}