Conditional Tags
Use conditional tags to render sections when variables match certain values. The two major conditional tags are if and unless. The if tag renders its contents if the condition is true, and the unless tag checks does the same if its condition is false. You can use operators like == in conditions to check equivalence.
Use the elsif and else tags to check for more than one condition in a block. Only one section will render, and a block will stop checking after one of its tags is selected. The elsif tag checks for another value, and else renders its section if no other sections are rendered.
Conditional tags sections should be closed with end followed by the tag name. For example, if sections are closed with endif.
Liquid Input
{% if user.username == "john_doe" %}
Welcome back!
{% elsif user.username == "jane_doe" %}
Hi Jane!
{% else %}
Who are you?
{% endif %}
{% unless user.username == "jane_doe" %}
You aren't Jane!
{% endunless %}
HTML Output
If user.username is john_doe.
Welcome back!
You aren't Jane!
If user.username is jane_doe.
Hi Jane!
If user.username is jake_doe.
Who are you?
You aren't Jane!
Case & When Tags
If you have a large number of conditions repeatedly checking a single value, like user.username, it can be easier to use case and when tags.
Liquid Input
{% case user.username %}
{% when 'john_doe' %}
Welcome back!
{% when 'jane_doe' %}
Hi Jane!
{% else %}
Who are you?
{% endcase %}
HTML Output
If user.username is john_doe.
Welcome back!
If user.username is jane_doe.
Hi Jane!
If user.username is jake_doe.
Who are you?