hugo/content/en/functions/compare/Default.md
Bjørn Erik Pedersen e509cac533 Squashed 'docs/' changes from 7ef2dbce4..cb18a5183
cb18a5183 Fix broken link
07a0198bf Config: Place Google Analytics tag ID under the services key
4bf0c719f Fix typo
50d8ad1af Fix muiltilingual menu definition instructions
1a32519a9 Fix typos
6f34ca8e0 Explain usage of front matter to target a template
5bd977257 Improve goldmark config docs
447632938 Remove Docker notes from installation instructions
84741d173 Update reference to hugo.work
0338d7c71 Fix menu template
f5d2f5ed4 Fix typos in content/en/functions/fmt
a3a40ff99 Add return type to functions
85ac3e779 Remove outdated feature image
d47d889e4 Fix signatures
7551ba28f Document safe.JSStr function
e77993be0 Document keyVals function
4dba20db3 Update theme
babf91544 Update echoparam
8c8203efa Adjust related functions
4cb1b30fc Fix example
ba95eca64 Improve showcase prose
5d3dcf366 Add Overmind Studios showcase
8d634ac70 Change code blocks from indented to fenced
cfab978e6 Add missing code fences
407dd5c47 Limit related pages for functions to other functions
9fa67d981 Fix .Site.LastChange doc
393aa16d0 netlify: Hugo 0.119.0
f864af97a docs: Even more about images.Process
9d772d5f0 docs: More about images.Process
bc655f869 docs: Regen docshelper
41c3536d1 Merge commit '9aec42c5452b3eb224888c50ba1c3f3b68a447e9'
918ed53f4 Add images.Process filter
573645883 Add $image.Process
a1151b0fd Add images.Opacity filter

git-subtree-dir: docs
git-subtree-split: cb18a5183fc62f301ffde50b8c39f03e4b897aec
2023-10-20 09:42:39 +02:00

88 lines
2.1 KiB
Markdown

---
title: compare.Default
linkTitle: default
description: Allows setting a default value that can be returned if a first value is not set.
categories: [functions]
keywords: []
menu:
docs:
parent: functions
function:
aliases: [default]
returnType: any
signatures: [compare.Default DEFAULT INPUT]
relatedFunctions:
- compare.Conditional
- compare.Default
aliases: [/functions/default]
---
`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:
{{< code file="content/posts/default-function-example.md" >}}
---
title: Sane Defaults
seo_title:
date: 2017-02-18
font:
oldparam: The default function helps make your templating DRYer.
newparam:
---
{{< /code >}}
`default` can be written in more than one way:
```go-html-template
{{ .Params.font | default "Roboto" }}
{{ default "Roboto" .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:
```go-html-template
{{ $old := .Params.oldparam }}
<p>{{ .Params.newparam | default $old }}</p>
```
Which would return:
```html
<p>The default function helps make your templating DRYer.</p>
```
And then using dot notation
```go-html-template
<title>{{ .Params.seo_title | default .Title }}</title>
```
Which would return
```html
<title>Sane Defaults</title>
```
The following have equivalent return values but are far less terse. This demonstrates the utility of `default`:
Using `if`:
```go-html-template
<title>{{ if .Params.seo_title }}{{ .Params.seo_title }}{{ else }}{{ .Title }}{{ end }}</title>
=> Sane Defaults
```
Using `with`:
```go-html-template
<title>{{ with .Params.seo_title }}{{ . }}{{ else }}{{ .Title }}{{ end }}</title>
=> Sane Defaults
```