title: How do you refer to custom javascript functions in your type script methods?
body: <p>Say, you have a simple Javascript function such as <code>sayHello()</code>:</p>
  
  <pre><code>function sayHello(){
     alert('Hello');
  }
  </code></pre>
  
  <p>and you put this in your app's <code>assets/js</code> folder as a custom library <code>assets/js/my-js-library.js</code> </p>
  
  <p>Then, finally, you refer to it from the <code>index.html</code> like this:</p>
  
  <pre><code>&lt;script src='http://example.com/assets/js/my-js-library.js'&gt;&lt;/script&gt;
  </code></pre>
  
  <p>What does it take in typescript  ( say in ngOnInit for example ) so you can do something like this?</p>
  
  <pre><code>ngOnInit () {
     sayHello();
  }
  </code></pre>
  
  <p>Or is it not possible? </p>