Reading time on Jekyll

reading-time.liquid

{% comment %} 
prints friendly human readable reading time 

divided_by doesn't round, so assuming 180 WPM we use:
<90  = 30 seconds
<270 = 1 minute
<450 = 2 minutes
<630 = 3 minutes
<810 = 4 minutes
<990 = 5 minutes
{% endcomment %}

{% assign words = content | number_of_words %}
{% if words <= 90 %}
{% assign reading_time = "30 sec" %}
{% elsif words < 270 %}
{% assign reading_time = "1 min" %}
{% elsif words < 450 %}
{% assign reading_time = "2 min" %}
{% elsif words < 630 %}
{% assign reading_time = "3 min" %}
{% elsif words < 810 %}
{% assign reading_time = "4 min" %}
{% elsif words < 990 %}
{% assign reading_time = "5 min" %}
{% else %}
{% assign reading_time = words | divided_by:180 | append:" min" %}
{% endif %}

{{ reading_time }}