Condition Expressions

This page covers everything you can write inside a Condition block — operators, nesting, and dynamic data.

A condition is any expression that evaluates to true or false. You type it in the Condition block's sidebar panel, and Unblock wraps your inner blocks with {% if expression %} / {% endif %}.

Existence

The simplest condition — check if a value exists and is not empty:

{% if post.thumbnail %}
{% if post.excerpt %}
{% if post.content %}
{% if user.id %}              {# user.id is 0 for guests #}

An existence check returns false for null, false, 0, empty strings, and empty arrays.

Comparison operators

Operator	Description	Example
==	Equal	post.post_status == 'publish'
!=	Not equal	post.post_status != 'draft'
===	Identical (strict)	post.comment_count === 0
!==	Not identical (strict)	post.type !== 'page'
>	Greater than	post.tags|length > 0
<	Less than	post.categories|length < 3
>=	Greater or equal	post.date('Y') >= '2024'
<=	Less or equal	post.date('Y') <= '2025'

{% if post.category.slug == 'featured' %}
{% if post.comment_count > 0 %}
{% if post.date('Y') == '2026' %}

Strict vs loose

Use === and !== (strict) when you need to distinguish between 0, false, null, and empty strings. Use == and != for general comparisons.

Logical operators

Operator	Description	Example
and	Both must be true	post.thumbnail and post.excerpt
or	At least one must be true	post.type == 'post' or post.type == 'page'
xor	Exactly one must be true	post.thumbnail xor post.excerpt
not	Negation	not post.thumbnail

{% if post.thumbnail and post.excerpt %}
{% if post.type == 'post' or post.type == 'page' %}
{% if post.thumbnail xor post.excerpt %}
{% if not post.thumbnail %}

Containment operators

Operator	Description	Example
in	Value is in a list	post.post_status in ['publish', 'future']
not in	Value is not in a list	post.post_status not in ['draft', 'trash']
starts with	String starts with	post.title starts with 'How'
ends with	String ends with	post.slug ends with '-draft'

{% if post.post_status in ['publish', 'future'] %}
{% if 'sale' in post.tags %}
{% if post.category.slug not in ['uncategorized', 'draft'] %}

Tests

Tests check a property of a value with is, or is not to negate:

Test	Description	Example
is defined	Value is not null	post.meta('subtitle') is defined
is empty	Value is empty (null, false, 0, '', [])	post.excerpt is empty
is null	Value is exactly null	post.parent is null
is even	Number is even	loop.index is even
is odd	Number is odd	loop.index is odd
is iterable	Value can be looped over	post.tags is iterable
is sequence	Value is a list (sequential array)	post.tags is sequence
is mapping	Value is a map (keyed array or object)	post.meta('data') is mapping
is divisible by(n)	Number divides evenly by n	loop.index is divisible by(3)
is same as(x)	Strictly identical, type and value	post.comment_count is same as(0)

{% if post.thumbnail is not empty %}
{% if loop.index is divisible by(2) %}
{% if post.excerpt is defined and post.excerpt is not empty %}

Nested conditions

Use parentheses to group logic and control evaluation order:

{% if post.post_status == 'publish' and (post.thumbnail or post.excerpt) %}

Without parentheses, and binds tighter than or. This means:

{# These are NOT the same: #}
{% if a and b or c %}        {# → (a and b) or c #}
{% if a and (b or c) %}      {# → a and (b or c) #}

You can nest as deep as needed:

{% if user.id and ('editor' in user.roles or ('author' in user.roles and post.author.id == user.id)) %}

Dynamic data in conditions

Conditions have full access to the same dynamic data you use in expressions — providers, methods, filters, and functions all work inside {% if %}.

Provider fields

Any field from any provider works in a condition:

{% if post.author.id == user.id %}
{% if site.language == 'fr' %}
{% if archive.type == 'category' %}
{% if 'administrator' in user.roles %}

Methods

Call methods with arguments:

{% if post.meta('is_featured') %}
{% if post.date('Y') == '2026' %}

Filters

Apply filters to transform values before comparing:

{% if post.title|length > 50 %}
{% if post.content|striptags|length > 1000 %}
{% if post.tags|length >= 3 %}

Variables

Use a Variable block to store a value, then check it in a Condition:

{% set subtitle = post.meta('subtitle') %}

{% if subtitle %}
    <p class="subtitle">{{ subtitle }}</p>
{% endif %}

Math

Arithmetic works inside conditions:

{% if loop.index + 1 <= 5 %}
{% if loop.index % 2 == 0 %}

Common mistake

Filters like |length return a number, not a boolean. Writing {% if post.tags|length %} works (non-zero is truthy), but {% if post.tags|length > 3 %} is clearer about your intent.

Next steps

• Condition patterns — real-world recipes for common scenarios
• Condition overview — how the Condition block works
• Expressions & Syntax — full operator and precedence reference