Combine posts from some but not all collections

1

I’m trying to create an array of pages from one or more (but not all) collections. Background, as you may guess from the code: I organize translations using collections and want to link to the translations that may or may not exist for each page. To do so, I want to create an array of all the pages that may be a translation, so that I can filter that array. This is what I came up with:

  {% assign page-translations = "" | split: "" %}
  {%- assign collections  = site.collections | where_exp: "item", "item.label != 'posts' and item.label != page.collection" -%}
  {%- for collection in collections -%}
    {% assign page-translations =  page-translations | concatenate collection %}
  {%- endfor -%}

This fails however, because Jekyll says “concat filter requires an array argument”. Apparently the collection isn’t an array. Of course I could create a template iterating through each collection, but by creating an array with the translations first, I can use that in several of my includes and avoid the need to do the filtering an additional two times.

I have a simple one liner solution already:

  {%- assign page-translations = site.documents | where: "translation-reference", page.translation-reference | where_exp: "item", "item.collection != page.collection" | sort: 'language' -%}

But I can imagine that becoming a performance issue, because it checks all documents instead of just the collections that may contain a translation.

Any ideas of how to combine pages from multiple collections?

1 Like
2

Hi @Koos, did you find a way to do it? I am trying to do the same thing, to loop through multiple collections, but facing the concatenation problem.

3

I didn’t find another solution, but realized the problem isn’t huge in my case, because I don’t expect the site to have many pages. If I understand it correctly, collections are for pages only, so I’d have to set up a similar lookup for posts, probably using categories.