default

Syntax

default DEFAULT INPUT

default checks whether a given value is set and returns a default value if it is not. Set in this context means different things depending on the data type:

• non-zero for numeric types and times
• non-zero length for strings, arrays, slices, and maps
• any boolean or struct value
• non-nil for any other types

default function examples reference the following content page:

---
title: Sane Defaults
seo_title:
date: 2017-02-18
font:
oldparam: The default function helps make your templating DRYer.
newparam:
---

default can be written in more than one way:

{{ index .Params "font" | default "Roboto" }}
{{ default "Roboto" (index .Params "font") }}

Both of the above default function calls return Roboto.

A default value, however, does not need to be hard coded like the previous example. The default value can be a variable or pulled directly from the front matter using dot notation:

{{$old := .Params.oldparam }}
<p>{{ .Params.newparam | default $old }}</p>

Which would return:

<p>The default function helps make your templating DRYer.</p>

And then using dot notation

<title>{{ .Params.seo_title | default .Title }}</title>

Which would return

<title>Sane Defaults</title>

The following have equivalent return values but are far less terse. This demonstrates the utility of default:

Using if:

<title>{{if .Params.seo_title}}{{.Params.seo_title}}{{else}}{{.Title}}{{end}}</title>
=> Sane Defaults

Using with:

<title>{{with .Params.seo_title}}{{.}}{{else}}{{.Title}}{{end}}</title>
=> Sane Defaults