Only fetch categories that are related to a minimum of entries

Question

Is there a way to only fetch categories that have been assigned to a minimum of entries, i.e. 4?

Currently I fetch categories like this:

{% set productIds = craft.entries.section('products').ids() %}
{% set categories = craft.categories.relatedTo({ sourceElement: productIds }) %}

I know I can now do the following to only display content for categories which have been assigned to at least four entries:

{% set entries = craft.entries.section('products').relatedTo(category) %}
{% if entries|length > 4 %}
  ...
{% endif %}

But is there a way to apply this logic to the craft.categories query?

Answer 1

What you can always do in situations, where the default parameters are not enough, is to "collect" element IDs and pass them to the id param of a new criteria model.

So loop through all categories and merge the category IDs matching you condition to an array:

{% set topCategoriesIds = mainCategoriesIds|merge([category.id]) %}

When you're done, get your filtered categories from these IDs:

{% set categories = craft.categories.id(topCategoriesIds) %}

Answer 2

Short answer: There is no way to apply this sort of logic to the craft.categories query. The way I have set this up is good. It can be improved performance wise by wrapping the queries around a {% cache %} tag.

As Carl has pointed out in his answer, the matching categories could also be merged into an array and added to a new query, which could then be used for pagination etc.