Writing Functions

Here are the general steps to create a function using your content and Hugo built-ins. Here are some general tips:

• printf or scratch for formatting and intermediate variables
• with, if, and range to conditionally render blocks
• .Site for global data, .Params for front matter

1. Start with the data:

   • .Content: rendered HTML
   • .RawContent: raw markdown source
   • .Title, .Date, .Params: common page fields

2. Apply functions with pipeline syntax:

   {{ $words := countwords .Content }}
   {{ $readingTime := div $words 250 }}
   

3. Use Hugo built-in functions:

   • countwords: counts words
   • len: gets length of lists/maps/strings
   • add, div, mul, sub: math
   • math.Round, math.Floor, math.Ceil
   • time, now, dateFormat
   • where, index, delimit, replace

For example, here we show the number of days since the page was last updated:

{{ $days := div (sub now.Unix .Lastmod.Unix) 86400 }}
<p>Updated {{ math.Floor $days }} days ago</p>