Configure build

This is the default configuration:

build:
  buildStats:
    disableClasses: false
    disableIDs: false
    disableTags: false
    enable: false
  cacheBusters:
  - source: '(postcss|tailwind)\.config\.(js|mjs|cjs)'
    target: (css|styles|scss|sass)
  cleanDestinationDir:
    enable: false
    keepDirs:
    - '{**/,}.*'
    keepFiles:
    - '{**/,}.{git,gitignore,gitattributes}'
  noJSConfigInAssets: false
  useResourceCacheWhen: fallback

[build]
  noJSConfigInAssets = false
  useResourceCacheWhen = 'fallback'
  [build.buildStats]
    disableClasses = false
    disableIDs = false
    disableTags = false
    enable = false
  [[build.cacheBusters]]
    source = '(postcss|tailwind)\.config\.(js|mjs|cjs)'
    target = '(css|styles|scss|sass)'
  [build.cleanDestinationDir]
    enable = false
    keepDirs = ['{**/,}.*']
    keepFiles = ['{**/,}.{git,gitignore,gitattributes}']

{
   "build": {
      "buildStats": {
         "disableClasses": false,
         "disableIDs": false,
         "disableTags": false,
         "enable": false
      },
      "cacheBusters": [
         {
            "source": "(postcss|tailwind)\\.config\\.(js|mjs|cjs)",
            "target": "(css|styles|scss|sass)"
         }
      ],
      "cleanDestinationDir": {
         "enable": false,
         "keepDirs": [
            "{**/,}.*"
         ],
         "keepFiles": [
            "{**/,}.{git,gitignore,gitattributes}"
         ]
      },
      "noJSConfigInAssets": false,
      "useResourceCacheWhen": "fallback"
   }
}

buildStats

See the build stats section below.

cachebusters

See the cache busters section below.

cleanDestinationDir

See the clean destination directory section below.

noJSConfigInAssets

(bool) Whether to disable writing a jsconfig.json in your assets directory with mapping of imports from running js.Build. This file is intended to help with intellisense/navigation inside code editors such as VS Code. Note that if you do not use js.Build, no file will be written.

useResourceCacheWhen

(string) When to use the resource file cache, one of never, fallback, or always. Applicable when transpiling Sass to CSS. Default is fallback.

Build stats

build:
  buildStats:
    disableClasses: false
    disableIDs: false
    disableTags: false
    enable: false

[build]
  [build.buildStats]
    disableClasses = false
    disableIDs = false
    disableTags = false
    enable = false

{
   "build": {
      "buildStats": {
         "disableClasses": false,
         "disableIDs": false,
         "disableTags": false,
         "enable": false
      }
   }
}

enable

(bool) Whether to create a hugo_stats.json file in the root of your project. This file contains arrays of the class attributes, id attributes, and tags of every HTML element within your published site. Use this file as data source when removing unused CSS from your site. This process is also known as pruning, purging, or tree shaking. Default is false.

disableIDs

(bool) Whether to exclude id attributes. Default is false.

disableTags

(bool) Whether to exclude element tags. Default is false.

disableClasses

(bool) Whether to exclude class attributes. Default is false.

Due to the nature of partial server builds, new HTML entities are added while the server is running, but old values will not be removed until you restart the server or run hugo build.

Cache busters

Use build.cachebusters to expire specific keys in the resource cache when a watched source file changes, triggering a rebuild of dependent resources such as CSS. For example, use this configuration when using the css.TailwindCSS function:

build:
  buildStats:
    enable: true
  cachebusters:
  - source: 'assets/notwatching/hugo_stats\.json'
    target: css
  - source: '(postcss|tailwind)\.config\.js'
    target: css
module:
  mounts:
  - source: assets
    target: assets
  - disableWatch: true
    source: hugo_stats.json
    target: assets/notwatching/hugo_stats.json
security:
  exec:
    allow:
    - ^(dart-)?sass$
    - ^go$
    - ^git$
    - ^node$
    - ^postcss$
    - ^tailwindcss$

[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'
[security]
  [security.exec]
    allow = ['^(dart-)?sass$', '^go$', '^git$', '^node$', '^postcss$', '^tailwindcss$']

{
   "build": {
      "buildStats": {
         "enable": true
      },
      "cachebusters": [
         {
            "source": "assets/notwatching/hugo_stats\\.json",
            "target": "css"
         },
         {
            "source": "(postcss|tailwind)\\.config\\.js",
            "target": "css"
         }
      ]
   },
   "module": {
      "mounts": [
         {
            "source": "assets",
            "target": "assets"
         },
         {
            "disableWatch": true,
            "source": "hugo_stats.json",
            "target": "assets/notwatching/hugo_stats.json"
         }
      ]
   },
   "security": {
      "exec": {
         "allow": [
            "^(dart-)?sass$",
            "^go$",
            "^git$",
            "^node$",
            "^postcss$",
            "^tailwindcss$"
         ]
      }
   }
}

When buildStats is enabled, Hugo writes a hugo_stats.json file on each build, containing the classes, IDs, and tags used in the rendered output. Changes to this file trigger a rebuild of the CSS. See the css.TailwindCSS function for a running example.

source

(string) A regular expression matching file(s) relative to one of the virtual component directories in Hugo, typically assets/....

target

(string) A regular expression matching the keys in the resource cache that should be expired when source changes. You can use the matching regexp groups from source in the expression, such as $1.

Clean destination directory

Hugo does not clear the public directory before building your project. Existing files are overwritten, but not deleted. This behavior is intentional, preventing the inadvertent removal of files that you may have added to the public directory after the build.

As a result, the public directory can accumulate stale files over time. For example, a rendered page may remain after you delete or rename its content file, or draft, expired, and future content may remain after it no longer meets the criteria for publication. Enable cleanDestinationDir to have Hugo remove these stale files automatically on every build.

This is the default configuration:

build:
  cleanDestinationDir:
    enable: false
    keepDirs:
    - '{**/,}.*'
    keepFiles:
    - '{**/,}.{git,gitignore,gitattributes}'

[build]
  [build.cleanDestinationDir]
    enable = false
    keepDirs = ['{**/,}.*']
    keepFiles = ['{**/,}.{git,gitignore,gitattributes}']

{
   "build": {
      "cleanDestinationDir": {
         "enable": false,
         "keepDirs": [
            "{**/,}.*"
         ],
         "keepFiles": [
            "{**/,}.{git,gitignore,gitattributes}"
         ]
      }
   }
}

enable

New in v0.167.0

(bool) Whether to clean the public directory before rendering the site. Hugo removes every file and directory in the public directory that does not have a corresponding static file, whether from the project’s static directory, a module mount, or a theme. This removes stale files, such as old rendered pages and deleted static assets, as well as files you added to the public directory yourself, such as a CNAME or _redirects file. Use the keepDirs and keepFiles settings to preserve specific directories and files. This cleanup runs even if the project has no static files. Default is false. Override this setting for a single build with the --cleanDestinationDir command line flag.

keepDirs

New in v0.167.0

([]string) A glob slice matching directories, relative to the public directory, to preserve when cleaning the destination directory. In a multilingual multihost project, patterns are relative to each language’s subdirectory of the public directory. A matching directory is kept along with everything beneath it, including subdirectories and their contents. The default value, shown above, matches directories whose names begin with a dot, wherever they occur in the directory tree. A value you set replaces the default rather than adding to it, so include the default pattern to continue preserving these directories.

keepFiles

New in v0.167.0

([]string) A glob slice matching files, relative to the public directory, to preserve when cleaning the destination directory. In a multilingual multihost project, patterns are relative to each language’s subdirectory of the public directory. The default value, shown above, matches .git, .gitignore, and .gitattributes files, wherever they occur in the directory tree. A value you set replaces the default rather than adding to it, so include the default pattern to continue preserving these files.