How to include script tag in index.html in karma testing

I am using chameleon script tag in my index.html page in my angular app as below:

<script type="text/javascript">function(){}...</script>

In my component.ts I am referencing chamaleon as below:

declare var chmln: any;

ngOnInit() {
    chmln.identify(usr.username)
}

But when I want to test my component.spec.ts ngOnInit method it gives me error chmln not found.

My question is how to include the scripts referenced in script tags into Karma testing? Any help is appreciated.

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Source Url How to include script tag in index.html in karma testing