How to get an {{ array }} via param into addon?

I have some variables I have to get into my addon: {{ collection:articles filter="ArticlePreviewFilter" mode="{categories}" categories="{categories_to_hide_or_show }" }} It works for "mode" with $this->get('mode') but not for categories because {categories_to_hide_or_show } is an array. Console says LOG.error: Cannot render an array variable as a string: {{ categories_to_hide_or_show }}. How do I get this array into my addon?