mirror of
https://github.com/gohugoio/hugo.git
synced 2024-12-01 19:33:08 -05:00
83 lines
2 KiB
Markdown
83 lines
2 KiB
Markdown
---
|
|
title: default
|
|
description: Allows setting a default value that can be returned if a first value is not set.
|
|
qref: "Returns a default value if a value is not set when checked."
|
|
keywords: [defaults]
|
|
categories: [functions]
|
|
menu:
|
|
docs:
|
|
parent: functions
|
|
toc:
|
|
signature: ["default DEFAULT INPUT"]
|
|
relatedfuncs: []
|
|
---
|
|
|
|
`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
|
|
```
|