I'm using libraries like amcharts that have many js files.
I put amcharts in web/js/amcharts as suggested julesbou and then
{% block javascripts %}
{{ parent() }}
{% javascripts '/js/amcharts/amcharts.js' %}
<script src="{{ asset_url }}" type="text/javascript"> </script>
{% endjavascripts %}
{% endblock %}
But I get [exception] 500 | Internal Server Error | RuntimeException
[message] The source file "/amcharts/amcharts.js" does not exist.