code = "var playlist = ['playlist1', 'playlist2'];"
return render_template('template.html', code=code)

<script type="text/javascript"> {{ code }} </script>

<script type="text/javascript"> var playlist = [&#39;playlist1&#39;, &#39;playlist2&#39;]; </script>

<script type="text/javascript"> var playlist = ['playlist1', 'playlist2']; </script>