These are all falsy, as you would expect.

  • False boolean. 
      my_bool: false
  • Undefined variable.
  • Null variable. 
      null_var: null
  • Empty variable. 
      empty_var:

Nil equivalents

These all rendered treated the same by Liquid and rendered as nil.

---
null_var: null
empty_var:
---

{{ page.undefined_var | inspect }}
{{ page.null_var | inspect }}
{{ page.empty_var | inspect }}

In YAML you need to define as null, but in Jekyll internally null values are stored as nil.