hugo/docs/content/en/templates/partials.md

207 lines
7.5 KiB
Markdown
Raw Normal View History

---
title: Partial Templates
linktitle: Partial Templates
description: Partials are smaller, context-aware components in your list and page templates that can be used economically to keep your templating DRY.
date: 2017-02-01
publishdate: 2017-02-01
lastmod: 2017-02-01
categories: [templates]
keywords: [lists,sections,partials]
menu:
docs:
parent: "templates"
weight: 90
weight: 90
sections_weight: 90
draft: false
aliases: [/templates/partial/,/layout/chrome/,/extras/analytics/]
toc: true
---
{{< youtube pjS4pOLyB7c >}}
## Partial Template Lookup Order
Partial templates---like [single page templates][singletemps] and [list page templates][listtemps]---have a specific [lookup order][]. However, partials are simpler in that Hugo will only check in two places:
1. `layouts/partials/*<PARTIALNAME>.html`
2. `themes/<THEME>/layouts/partials/*<PARTIALNAME>.html`
This allows a theme's end user to copy a partial's contents into a file of the same name for [further customization][customize].
## Use Partials in your Templates
All partials for your Hugo project are located in a single `layouts/partials` directory. For better organization, you can create multiple subdirectories within `partials` as well:
```
.
└── layouts
└── partials
├── footer
│   ├── scripts.html
│   └── site-footer.html
├── head
│   ├── favicons.html
│   ├── metadata.html
│   ├── prerender.html
│   └── twitter.html
└── header
├── site-header.html
└── site-nav.html
```
All partials are called within your templates using the following pattern:
```
{{ partial "<PATH>/<PARTIAL>.html" . }}
```
{{% note %}}
One of the most common mistakes with new Hugo users is failing to pass a context to the partial call. In the pattern above, note how "the dot" (`.`) is required as the second argument to give the partial context. You can read more about "the dot" in the [Hugo templating introduction](/templates/introduction/).
{{% /note %}}
{{% note %}}
`<PARTIAL>` including `baseof` is reserved. ([#5373](https://github.com/gohugoio/hugo/issues/5373))
{{% /note %}}
As shown in the above example directory structure, you can nest your directories within `partials` for better source organization. You only need to call the nested partial's path relative to the `partials` directory:
```
{{ partial "header/site-header.html" . }}
{{ partial "footer/scripts.html" . }}
```
### Variable Scoping
The second argument in a partial call is the variable being passed down. The above examples are passing the `.`, which tells the template receiving the partial to apply the current [context][context].
This means the partial will *only* be able to access those variables. The partial is isolated and *has no access to the outer scope*. From within the partial, `$.Var` is equivalent to `.Var`.
## Returning a value from a Partial
In addition to outputting markup, partials can be used to return a value of any type. In order to return a value, a partial must include a lone `return` statement.
## Inline partials
{{< new-in "0.74.0" >}}
You can also define partials inline in the template. But remember that template namespace is global, so you need to make sure that the names are unique to avoid conflicts.
```go-html-template
Value: {{ partial "my-inline-partial" . }}
{{ define "partials/my-inline-partial" }}
{{ $value := 32 }}
{{ return $value }}
{{ end }}
```
### Example GetFeatured
```go-html-template
{{/* layouts/partials/GetFeatured.html */}}
Squashed 'docs/' changes from 9cece6640..fb551cc75 fb551cc75 Update index.md 7af894857 Update index.md d235753ea Hugo 0.82.1 e03e72deb Merge branch 'temp0821' e62648961 Merge branch 'release-0.82.1' e1ab0f6eb releaser: Add release notes to /docs for release of 0.82.1 5d354c38d Replaced ``` code blocks with Code Toggler c9d065c20 Remove duplicate YAML keys (#1420) 8ae31e701 Add webp image encoding support 848f2af26 Update internal.md (#1407) c103a86a4 Fix `ref` shortcode example output (#1409) 9f8ba56dc Remove leading dot from where function KEY (#1419) 363251a51 Improve presentation of template lookup order (#1382) b73da986d Improve description of Page Resources (#1381) 4e0bb96d5 Rework robots.txt page (#1405) edf893e6f Update migrations.md (#1412) 450f1580b Add link to `site` function doc (#1417) cfffa6e6f Added one extension to the list (#1414) 05f1665a0 Update theme 5de0b1c6a Update theme 250e20552 Add hugo.IsExtended dea5e1fd7 Fix typo on merge function page (#1408) 1bbed2cf3 Update configuration.md be0b64a46 Omit ISO cbb5b8367 Fix `dateFormat` documentation 698f15466 Regenerate the docshelper f9a8a7cb6 Update multilingual.md a22dc6267 Fix grammar (#1398) eb98b0997 Fix pretty URL example (#1397) f4c4153dc Mention date var complementation in post scheduling (#1396) 17fae284c Fix resources.ExecuteAsTemplate argument order (#1394) 97e2c2abb Use code-toggle shortcode in `multilingual.md` (#1388) 3a84929bb Harmonize capitalization (#1393) 17f15daa6 fix file naming used in example (#1392) 5d97b6a18 Add slice syntax to sections permalinks config 00665b97b Improve description of `site.md` edcf5e3fc Fix example in `merge.md` f275ab778 Update postprocess.md 9593e3991 Fix file name 59bd9656f Update postprocess.md 1172fb6d0 Update to theNewDynamic repository (#1263) f5b5c1d2c Update Hugo container image 4f2e92f2a Adapt anchorize.md to Goldmark 98aa19073 Directly link to `highlight` shortcode (#1384) 4c75c2422 Fix header level f15c06f23 markdownify: add note about render-hooks and .RenderString (#1281) 69c82eb68 Remove Blackfriday reference from shortcode desc (#1380) 36de478df Update description of ignoreFiles config setting (#1377) 6337699d8 Remove "Authors" page from documentation (#1371) 35e73ca90 fix indent in example (#1372) d3f01f19a Remove opening body tag from header example (#1376) 341a5a7d8 Update index.md c9bfdbee6 Release 0.82.0 119644949 releaser: Add release notes to /docs for release of 0.82.0 32efaed78 docs: Regenerate docs helper dea5449a2 docs: Regen CLI docs eeab18fce Merge commit '81689af79901f0cdaff765cda6322dd4a9a7ccb3' d508a1259 Attributes for code fences should be placed after the lang indicator only c80905cef deps: Update to esbuild v0.9.0 95350eb79 Add support for Google Analytics v4 02d36f9bc Allow markdown attribute lists to be used in title render hooks 7df220a64 Merge commit '9d31f650da964a52f05fc27b7fb99cf3e09778cf' d80bf61b7 Fixes #7698. git-subtree-dir: docs git-subtree-split: fb551cc750faa83a1493b0e0d0898cd98ab74465
2021-04-20 18:21:45 +00:00
{{ return first . (where site.RegularPages "Params.featured" true) }}
```
```go-html-template
{{/* layouts/index.html */}}
{{ range partial "GetFeatured.html" 5 }}
[...]
{{ end }}
```
### Example GetImage
```go-html-template
{{/* layouts/partials/GetImage.html */}}
{{ $image := false }}
{{ with .Params.gallery }}
{{ $image = index . 0 }}
{{ end }}
{{ with .Params.image }}
{{ $image = . }}
{{ end }}
{{ return $image }}
```
```go-html-template
{{/* layouts/_default/single.html */}}
{{ with partial "GetImage.html" . }}
[...]
{{ end }}
```
{{% note %}}
Only one `return` statement is allowed per partial file.
{{% /note %}}
## Cached Partials
The [`partialCached` template function][partialcached] can offer significant performance gains for complex templates that don't need to be re-rendered on every invocation. The simplest usage is as follows:
```
{{ partialCached "footer.html" . }}
```
You can also pass additional parameters to `partialCached` to create *variants* of the cached partial.
For example, you can tell Hugo to only render the partial `footer.html` once per section:
```
{{ partialCached "footer.html" . .Section }}
```
If you need to pass additional parameters to create unique variants, you can pass as many variant parameters as you need:
```
{{ partialCached "footer.html" . .Params.country .Params.province }}
```
Note that the variant parameters are not made available to the underlying partial template. They are only use to create a unique cache key.
### Example `header.html`
The following `header.html` partial template is used for [spf13.com](https://spf13.com/):
{{< code file="layouts/partials/header.html" download="header.html" >}}
<!DOCTYPE html>
<html class="no-js" lang="en-US" prefix="og: http://ogp.me/ns# fb: http://ogp.me/ns/fb#">
<head>
<meta charset="utf-8">
{{ partial "meta.html" . }}
<base href="{{ .Site.BaseURL }}">
<title> {{ .Title }} : spf13.com </title>
<link rel="canonical" href="{{ .Permalink }}">
{{ if .RSSLink }}<link href="{{ .RSSLink }}" rel="alternate" type="application/rss+xml" title="{{ .Title }}" />{{ end }}
{{ partial "head_includes.html" . }}
</head>
{{< /code >}}
{{% note %}}
The `header.html` example partial was built before the introduction of block templates to Hugo. Read more on [base templates and blocks](/templates/base/) for defining the outer chrome or shell of your master templates (i.e., your site's head, header, and footer). You can even combine blocks and partials for added flexibility.
{{% /note %}}
### Example `footer.html`
The following `footer.html` partial template is used for [spf13.com](https://spf13.com/):
{{< code file="layouts/partials/footer.html" download="footer.html" >}}
<footer>
<div>
<p>
&copy; 2013-14 Steve Francia.
<a href="https://creativecommons.org/licenses/by/3.0/" title="Creative Commons Attribution">Some rights reserved</a>;
please attribute properly and link back.
</p>
</div>
</footer>
{{< /code >}}
[context]: /templates/introduction/ "The most easily overlooked concept to understand about Go templating is how the dot always refers to the current context."
[customize]: /themes/customizing/ "Hugo provides easy means to customize themes as long as users are familiar with Hugo's template lookup order."
[listtemps]: /templates/lists/ "To effectively leverage Hugo's system, see how Hugo handles list pages, where content for sections, taxonomies, and the homepage are listed and ordered."
[lookup order]: /templates/lookup-order/ "To keep your templating dry, read the documentation on Hugo's lookup order."
[partialcached]: /functions/partialcached/ "Use the partial cached function to improve build times in cases where Hugo can cache partials that don't need to be rendered with every page."
[singletemps]: /templates/single-page-templates/ "The most common form of template in Hugo is the single content template. Read the docs on how to create templates for individual pages."
[themes]: /themes/