title: Angular 2 and ActionCable integration
body: <p>I'm trying to make a Angular2 app (bootstrapped with angular-cli) work with Rails's ActionCable by integrating this lib on the frontend <a href="https://github.com/mwalsher/actioncable-js" rel="nofollow">https://github.com/mwalsher/actioncable-js</a></p>
  
  <p>I npm installed the lib,</p>
  
  <p>added this to angular-cli-build.js</p>
  
  <pre><code>'actioncable-js/index.js',
  </code></pre>
  
  <p>and this in system-config.ts:</p>
  
  <pre><code>/** Map relative paths to URLs. */
  const map: any = {
    'moment': 'vendor/moment/moment.js',
    'ng2-bootstrap': 'vendor/ng2-bootstrap',
    'lodash': 'vendor/lodash',
    'actioncable-js': 'vendor/actioncable-js'
  };
  
  /** User packages configuration. */
  const packages: any = {
  
    'ng2-bootstrap': {
      format: 'cjs',
      defaultExtension: 'js',
      main: 'ng2-bootstrap.js'
  
    },
    'actioncable-js':{
      main: 'index.js'
    },
    'moment':{
      format: 'cjs'
    },
    'lodash':{
      main: "lodash.js"
    }
  };
  </code></pre>
  
  <p>added this to my component:</p>
  
  <pre><code>import { ActionCable } from 'actioncable-js';
  </code></pre>
  
  <p>but the build errors with this message:</p>
  
  <blockquote>
    <p>Cannot find module 'actioncable-js'.</p>
  </blockquote>
  
  <p>anyone has any idea why?</p>
  
  <p>My guess is typings are missing, but I'm not sure how to fix this.</p>