Check if Category is in Query

Question

I'm trying to check to see if a particular category (In a loop) exists in a query submitted from a search form.

At the moment I'm doing this inside a 'childCategory' loop...

{% for childCategory in childCategories %}

    {% for category in query %}{% if childCategory.slug == category.slug %} checked{% endif %}{% endfor %}

{% endfor %}

EUGH right?

Is there a better way (Surely!) to check to see if the cateogry exists? I've tried the length and indexOf filters as well as an IN conditional. Nothing works.

The query is being set like this:

{% set query = craft.request.getParam('category') %}
{% set queryCategories = craft.categories.group('opportunities').slug(query) %}

Answer 1

I would construct an array of the category slugs outside of your childCategories loop (using twig's merge filter:

{% set queryCatSlugs = [] %}
{% for category in query %}
  {% set queryCatSlugs = queryCatSlugs|merge([category.slug]) %}
{% endfor %}

Then your childCategories loop can use twig's containment operator (in) for the test:

{% for childCategory in childCategories %}
  {% if childCategory.slug in queryCatSlugs %}
    ... matches ...
  {% endif %}
{% endfor %}

Answer 2

In Craft 3 you don't have to iterate through the chidlCategories manually, you could use the column filter instead, like this:

{% set queryCatSlugs = childCategories.all() | column('slug') %}
{% if slugToCheck in queryCatSlugs %}
    ....
{% endif %}