Liquid
<h4>Good way, using == blank check</h4>
{% unless settings.featured_product == blank or all_products[settings.featured_product] == blank %}
{{ all_products[settings.featured_product].title }}<br>
{% endunless %}
<h4>Bad way, not using == blank check, all_products['anything'] will always be truthy</h4>
{% if all_products['rubbish-handle'] %}
{{ all_products['rubbish-handle'].title }}
{% else %}
No product exists with handle “rubbish-handle”.<br>
{% endif %}
<h4>Good way, using != blank check</h4>
{% if all_products['rubbish-handle'] != blank %}
{{ all_products['rubbish-handle'].title }}
{% else %}
No product exists with handle “rubbish-handle”.<br>
{% endif %}
<h4>Another good way, using .empty? check</h4>
{% unless settings.featured_product == blank or all_products[settings.featured_product].empty? %}
{{ all_products[settings.featured_product].title }}
{% else %}
No product exists with handle “{{ settings.featured_product }}”.<br>
{% endunless %}
Output
Good way, using == blank check
Camp Stool
Bad way, not using == blank check, all_products['anything'] will always be truthy
Good way, using != blank check
No product exists with handle “rubbish-handle”.
Another good way, using .empty? check
Camp Stool