Subscribe

controllers.application.js

import Ember from 'ember';
import subscribe from '../subscribe';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  myService: Ember.inject.service('my-service'),
  
  foos: 0,
  onFoo: subscribe('myService.foo', function() {
  this.incrementProperty('foos');
})
  
});

services.my-service.js

import Ember from 'ember';

export default Ember.Service.extend(Ember.Evented, {
  init() {
    this._super();
    setInterval(() => {
      this.trigger('foo', { id: Date.now() });
    }, 3000);
  }
});

subscribe.js

import Ember from 'ember';

const {
  assert,
  on
} = Ember;

export default function subscribe(path, method) {
  let [service, event, err] = path.split('.');
  let _listener = null;

  assert(`'subscribe()' expects a path with exactly one leaf, given ${path}`, event && service && !err);

  let computedFn = function() {
    if (!this.get(service) || _listener) {
      return;
    }

    // ensure teardown
    let _super = this.get('willDestroy');
    this.set('willDestroy', function() {
      this.get(service).off(event, _listener);
      _listener = null;
      computedFn = null;
      _super();
    });

    // proxy the event
    _listener = (e) => {
      method.call(this, e);
    };

    // subscribe to the event
    this.get(service).on(event, _listener);
  };

  return on.call(this, 'init', computedFn);
}

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<h2>The Foo Event has triggered {{foos}} times</h2>
<br>
{{outlet}}
<br>
<br>

twiddle.json

{
  "version": "0.7.1",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "https://cdnjs.cloudflare.com/ajax/libs/ember.js/2.4.3/ember.debug.js",
    "ember-data": "https://cdnjs.cloudflare.com/ajax/libs/ember-data.js/2.4.3/ember-data.js",
    "ember-template-compiler": "https://cdnjs.cloudflare.com/ajax/libs/ember.js/2.4.3/ember-template-compiler.js"
  }
}