title: How to use environment variable in index.html for Angular 6
body: <p>I am using angular6, in my project I am using Facebook Account Toolkit for mobile verification purpose.</p>
  
  <p>I need to initialise Account toolkit in index.html file using following code.</p>
  
  <pre><code>  AccountKit.init({
     appId:"XX",
     state:"xx",
     version:"v1.2",
     fbAppEventsEnabled:true,
     debug:true
   });
  </code></pre>
  
  <p>The problem is, values for <strong>appId</strong> and <strong>state</strong> change depending on environment (development/test/production).</p>
  
  <p>How can I use environment variables in <code>index.html</code> file.</p>
  
  <p>Please let me know if anyone has a solution for angular 6.</p>
  
  <p>Thanks in advance.</p>