---
title: templates.Defer
description: Defer execution of a template until after all sites and output formats have been rendered.
categories: []
keywords: []
params:
functions_and_methods:
aliases: []
returnType: string
signatures: [templates.Defer OPTIONS]
aliases: [/functions/templates.defer]
---
{{< new-in 0.128.0 />}}
> [!note]
> This feature should only be used in the main page template, typically `layouts/baseof.html`. Using it in shortcodes, partials, or render hook templates may lead to unpredictable results. For further details, please refer to [this issue].
[this issue]: https://github.com/gohugoio/hugo/issues/13492#issuecomment-2734700391
In some rare use cases, you may need to defer the execution of a template until after all sites and output formats have been rendered. One such example could be [TailwindCSS](/functions/css/tailwindcss/) using the output of [hugo_stats.json](/configuration/build/) to determine which classes and other HTML identifiers are being used in the final output:
```go-html-template {file="layouts/baseof.html" copy=true}
...
{{ with (templates.Defer (dict "key" "global")) }}
{{ partial "css.html" . }}
{{ end }}
...
```
```go-html-template {file="layouts/_partials/css.html" copy=true}
{{ with resources.Get "css/main.css" }}
{{ $opts := dict "minify" (not hugo.IsDevelopment) }}
{{ with . | css.TailwindCSS $opts }}
{{ if hugo.IsDevelopment }}
{{ else }}
{{ with . | fingerprint }}
{{ end }}
{{ end }}
{{ end }}
{{ end }}
```
> [!note]
> This function only works in combination with the `with` keyword.
>
> Variables defined on the outside are not visible on the inside and vice versa. To pass in data, use the `data` [option](#options).
For the above to work well when running the server (or `hugo -w`), you want to have a configuration similar to this:
{{< code-toggle file=hugo >}}
[build]
[build.buildStats]
enable = true
[[build.cachebusters]]
source = 'assets/notwatching/hugo_stats\.json'
target = 'css'
[[build.cachebusters]]
source = '(postcss|tailwind)\.config\.js'
target = 'css'
[module]
[[module.mounts]]
source = 'assets'
target = 'assets'
[[module.mounts]]
disableWatch = true
source = 'hugo_stats.json'
target = 'assets/notwatching/hugo_stats.json'
{{< /code-toggle >}}
## Options
The `templates.Defer` function takes a single argument, a map with the following optional keys:
key (`string`)
: The key to use for the deferred template. This will, combined with a hash of the template content, be used as a cache key. If this is not set, Hugo will execute the deferred template on every render. This is not what you want for shared resources like CSS and JavaScript.
data (`map`)
: Optional map to pass as data to the deferred template. This will be available in the deferred template as `.` or `$`.
```go-html-template
Language Outside: {{ site.Language.Lang }}
Page Outside: {{ .RelPermalink }}
I18n Outside: {{ i18n "hello" }}
{{ $data := (dict "page" . )}}
{{ with (templates.Defer (dict "data" $data )) }}
Language Inside: {{ site.Language.Lang }}
Page Inside: {{ .page.RelPermalink }}
I18n Inside: {{ i18n "hello" }}
{{ end }}
```
The [output format](/configuration/output-formats/), [site](/methods/page/site/), and [language](/methods/site/language) will be the same, even if the execution is deferred. In the example above, this means that the `site.Language.Lang` and `.RelPermalink` will be the same on the inside and the outside of the deferred template.