Drupal 8 - Get values as taxonomy term names from a taxonomy term reference field and print them out in a Twig template as classes. Especially handy for using with Isotope filters.

gistfile1.txt

{# Create classes array. The 'node' class is required for contextual edit links. #}
{% set categories = [] %}
{% set classes = ['integration', 'node'] %}

{% for key, item in content.field_integration_cat if key|first != '#' %}
  {% set categories = categories | merge([ item['#title'] | replace({' ':''}) ]) %}
{% endfor %}

{% for item in categories %}
  {% set classes = classes | merge([item]) %}
{% endfor %}


<section {{ attributes.addClass(classes) }}>

</section>