Liquid - Whitespace control
In Liquid, you can include a hyphen in your tag syntax {{-, -}}, {%-, and -%} to strip whitespace from the left or right side of a rendered tag.
Normally, even if it doesn’t output text, any line of Liquid in your template will still output a blank line in your rendered HTML:
Input
{% assign my_variable = "tomato" %}
{{ my_variable }}
Notice the blank line before “tomato” in the rendered template:
Output
tomato
Strip whitespace in assign
By including hyphens in your assign tag, you can strip the generated whitespace from the rendered template:
Input
{%- assign my_variable = "tomato" -%}
{{ my_variable }}
Output
tomato
If you don’t want any of your tags to output whitespace, as a general rule you can add hyphens to both sides of all your tags ({%- and -%}):
Input
{% assign username = "John G. Chalmers-Smith" %}
{% if username and username.size > 10 %}
Wow, {{ username }}, you have a long name!
{% else %}
Hello there!
{% endif %}
Output without whitespace control
Wow, John G. Chalmers-Smith, you have a long name!
Input
{%- assign username = "John G. Chalmers-Smith" -%}
{%- if username and username.size > 10 -%}
Wow, {{ username }}, you have a long name!
{%- else -%}
Hello there!
{%- endif -%}
Output with whitespace control
Wow, John G. Chalmers-Smith, you have a long name!
Note
This topic is a compilation of knowledge found at: Shopify Themes, Liquid Documentation, Liquid Gem Documentation, and Liquid for Designers.