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default | Allows setting a default value that can be returned if a first value is not set. | Returns a default value if a value is not set when checked. | 2017-02-01 | 2017-02-01 | 2017-02-01 |
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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 date 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:
{{ 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:
{{< code file="variable-as-default-value.html" nocopy="true" >}} {{$old := .Params.oldparam }}
{{ .Params.newparam | default $old }}
{{< /code >}}Which would return:
<p>The default function helps make your templating DRYer.</p>
And then using dot notation
{{< code file="dot-notation-default-value.html" >}}
{{< /code >}}Which would return
{{< output file="dot-notation-default-return-value.html" >}}
{{< /output >}}The following have equivalent return values but are far less terse. This demonstrates the utility of default
:
Using if
:
{{< code file="if-instead-of-default.html" nocopy="true" >}}
=> Sane Defaults {{< /code >}}Using with
:
{{< code file="with-instead-of-default.html" nocopy="true" >}}
=> Sane Defaults {{< /code >}}