title: How to create a angular library with external js library?
body: <p>I have an angular cli project, which aims to be a feature library and used in another project. In my library project, I used some javascript library (no typescript file in it) in the component typescript file as following:</p>
  
  <pre><code>import * as L from 'leaflet';
  this.leafletMap = L.map('mapid');
  </code></pre>
  
  <p>My feature library project itself works fine when running <code>ng serve</code>. However, if I publish my library and install it in the testing project, the console will complain</p>
  
  <blockquote>
    <p>ERROR ReferenceError: L is not defined.</p>
  </blockquote>
  
  <p>Can anyone help me to solve this issues?</p>