Use backspace parameter on Stash nested get_list

Question

I'm using Stash to capture a list of articles. I'm trying to keep my viewModel separate from my view markup.

For each article, I'm capturing a nested list of categories.

In the view, I want to output comma-separated categories. I was under the impression that I could use backspace="x" on a get_list, but it doesn't seem to work. I am I going about this incorrectly?

I suppose I could use an if/else with 'count' and 'total_results' to remove the final comma and space, but would also like to know if backspace can work.

Set article list

{!-- Articles --}
{exp:stash:set_list name="articles" parse_tags="yes" parse_depth="2"}
    {exp:channel:entries
        channel="news"
        dynamic="no"
        orderby="sticky|entry_date"
        sort="desc|desc"
        sort_type="numeric|numeric"
        disable="member_data|category_fields"
        {triggers:entries}
    }
        {stash:id}{entry_id}{/stash:id}
        {stash:sticky}{sticky}{/stash:sticky}
        {stash:title}{title}{/stash:title}
        {stash:summary}{article_summary}{/stash:summary}
        {stash:date}{entry_date}{/stash:date}
        {stash:url}{page_url}{/stash:url}
        {stash:image}{article_featured_image}{/stash:image}

        {exp:stash:set_list:nested name="this_article_categories" parse_tags="yes" context="{entry_id}"}
            {categories}
                {stash:category_name}{category_name}{/stash:category_name}
                {stash:category_url_title}{category_url_title}{/stash:category_url_title}
            {/categories}
        {/exp:stash:set_list:nested}
    {/exp:channel:entries}
{/exp:stash:set_list}

Get Articles (See the get_list:nested name="this_article_categories" in the code below.)

{!-- Get Articles --}
{exp:stash:get_list name="articles" prefix="news" paginate="bottom" limit="15"}
<article>
    <header>
        <div class="meta">
            {news:date format="%M %j, %Y"} in {exp:stash:get_list:nested name="this_article_categories" backspace="2" context="{news:id}"}
                <a href="/news-events/news/category/{category_url_title}">{category_name}</a>, 
            {/exp:stash:get_list:nested}
        </div>
        <h1 class="gamma"><a href="{news:url}">{news:title}</a></h1>
    </header>
    <div class="article-body">
        {news:summary}
    </div>
    <p class="read-more"><a href="{news:url}">Continue reading <i class="ss-gizmo ss-right"></i></a></p>
</article>

<hr>

{/exp:stash:get_list}

Answer 1

The backspace parameter can be used with {exp:stash:get_list}, however be aware that any trailing whitespace and line breaks will count as 'spaces'.

{!-- Desired output - no trailing comma --}
Product 1, Products 2, Product 3

{!-- this won't work because of the line break after the comma --}
{exp:stash:get_list name="products" backspace="1"}
   {title},
{/exp:stash:get_list}

{!-- Either close the space up manually... --}
{exp:stash:get_list name="products" backspace="1"}{title},{/exp:stash:get_list}

{!-- ...or use the trim parameter --}
{exp:stash:get_list name="products" trim="y"}
   {title},
{/exp:stash:get_list}