Truthy and falsy

When a non-boolean data type is used in a boolean context (such as a conditional tag), Liquid decides whether to evaluate it as true or false. Data types that return true by default are called truthy. Data types that return false by default are called falsy.

Truthy

All values in Liquid are truthy except nil and false.

In the example below, the text “Tobi” is not a boolean, but it is truthy in a conditional:

{% assign name = "Tobi" %}

{% if name %}
  This text will always appear since "name" is defined.
{% endif %}

Strings, even when empty, are truthy. The example below will create empty HTML tags if page.category exists but is empty:

Input

{% if page.category %}
  <h1>{{ page.category }}</h1>
{% endif %}

Output

  <h1></h1>

Falsy

The only values that are falsy in Liquid are nil and false.

Summary

The table below summarizes what is truthy or falsy in Liquid.