Checking if related entries are live in a for loop and setting a variable based on the results

Question

So I have a section called children and these are related to various other entries include users. I am fetching all the children for the currentUser like so and eager-loading all the other relationships.

{% set childrenQuery = craft.entries
  .section('children')
  .relatedTo({
  sourceElement: currentUser,
  field: 'relatedChildren'
})
  .with([
  'associatedTerm',
  'tuitionClass',
  'tuitionClass.location'
]) %}

{% set children = childrenQuery.all() %}

What I then want to do is split out children in to 'Active' and 'Inactive' depending on if the related field associatedTerm is live.

I can do this fine like this;

Children (active)<br />
<ul class="list-disc mb-6">
  {% for child in children if child.associatedTerm|length %}
    <li>{{ child.firstName }} {{ child.surname }}</li>
    <li>{{ child.tuitionClass[0] }}</li>
    <li>{{ child.associatedTerm[0] }}</li>
    <li>{{ child.tuitionClass[0].location[0] }}</li>
  {% endfor %}
</ul>

Children Inactive ()<br />
  <ul class="list-disc mb-6">
    {% for child in children if not child.associatedTerm|length %}
      <li>{{ child.firstName }} {{ child.surname }}</li>
    {% endfor %}
  </ul>

However, what I want to do is actually do this logic first, so I can then wrap the active/inactive blocks into if statements, if there are in fact any active or inactive children as I have other code (headings and text) I want to show within the block and not appear at all if they are no entries.

So I am stuck on how to do this {% for child in children if not child.associatedTerm|length %} without a for loop and just check if there are any entries that exist.

I can achieve it like this; but it feels a little weird.

{% set childrenAreInactive = '' %}
{% for child in children if not child.associatedTerm|length %}
  {% set childrenAreInactive = 1 %}
{% endfor %}

Anyone have any ideas for a better method?

Answer 1

You're looking for the filter filter: https://docs.craftcms.com/v3/dev/filters.html#filter

Specifically something like this (untested):

{% set activeChildren = children|filter(child => child.associatedTerm|length) %}
{% set inactiveChildren = children|filter(child => child.associatedTerm|length == 0) %}

You now have two unique arrays to do with as you please:

{% if activeChildren|length %}
   <h2>You have active children</h2>
{% endif %}
<p class="{{ inactiveChildren|length ? 'inactiveChildren' }}">Hi there</p>

Whenever you get the sneaky feeling that a loop is overkill, look to map filter and reduce: these 3 methods are all like loops in disguise, in that they iterate through arrays and return something new based on the logic you supply.