Editing the Configuration Options

Pattern Lab Node comes with a configuration file (patternlab-config.json) that allows you to modify certain aspects of the system. The latest default values are included within. This file is shipped within the editions or can be supplied from core and the command line interface. Below is a description of each configuration option and how it affects Pattern Lab Node.


Instructs Pattern Lab to append a unique query string to Javascript and CSS assets throughout the frontend.

"cacheBust": true

default: true


Sets whether or not to delete public.patterns/ upon each build of Pattern Lab. When set to false, incremental builds are also enabled.

default: true


Sets a specific pattern upon launch of the styleguide. This pattern will not be available in the navigation, or in view all pages. The only way to get to it will be via a refresh. Set it using the short-hand pattern-include syntax:

"defaultPattern": "pages-welcome",

A special value of all can also be supplied to display all patterns on load.

default: all


Sets whether or not you want the styleguide to load with the pattern info open or closed.

default: false

defaultInitialViewportWidth (optional)permalink

Possibility to define whether the initial viewport width on opening pattern lab in the browser should take the default of 100% (value true) or take the (permanently) persisted value after the users have interacted with the viewport resize buttons previously (value false). This is especially beneficial in case that you'd expect the pages in full viewport at revisits, and even further if your startpage is defined as a "static" markdown welcome / orientation page.

default: false

defaultPatternInfoPanelCode (optional)permalink

Sets default active pattern info code panel by file extension - if unset, uses the value out of patternExtension config value, or instead use value html to display the html code initially, or the value defined for the patternExtension.

default: patternExtension value ("hbs" | "mustache" | "twig" | "html")


Sets whether or not to hide navigation options within the styleguide.


"ishControlsHide": {
"s": false,
"m": false,
"l": false,
"full": false,
"random": false,
"disco": false,
"hay": true,
"mqs": false,
"find": false,
"views-all": false,
"views-annotations": false,
"views-code": false,
"views-new": false,
"tools-all": false,
"tools-docs": false


Sets the boundaries of each of the viewport toggles, 'S'mall, 'M'edium, and 'L'arge. Clicking on one of these buttons will randomly set the ish Viewport to a value within the given range. Setting the range to the same number can effectively set an exact value. The first entry in ishViewportRange.s is the ishViewportMinimum, which is now obsolete. The second entry in ishViewportRange.l is the ishViewportMaximum, which is now also obsolete.


"ishViewportRange": {
"s": [240, 500],
"m": [500, 800],
"l": [800, 2600]


Sets the level of verbosity for Pattern Lab Node logging.

  • error will output a message as a thrown error
  • warning will output all warnings plus above
  • info will output all info messages, plus above (intended default)
  • debug will output all debug messages, plus above
  • quiet will output ZERO logs

This replaces the now obsolete debug flag.

default: info

noIndexHtmlremoval (optional)permalink

You might host your pattern lab in an environment that doesn't acknowledge the default file to be index.html in case that none is provided – Gitlab Pages is an example for this, where you might publish your preview builds to during development. So in case that you get a URL like <PATH>/index.html, it will redirect to <PATH>/?p=all. You might not be able to share this resulting URL or even do a refresh of the page, as the server would respond with a 404 error.

To disable this redirect which is similar to how Single Page Applications work, you could set the optional configuration "noIndexHtmlremoval" to true.

default: false


Sets the naming of output pattern files. Suffixes are defined for 'rendered', 'rawTemplate', and 'markupOnly' files. This configuration is needed for some PatternEngines that use the same input and output file extensions. Most users will not have to change this.

"outputFileSuffixes": {
"rendered": ".rendered",
"rawTemplate": "",
"markupOnly": ".markup-only"


Sets the configurable source and public directories for files Pattern Lab Node operates within. Build, copy, output, and server operations rely upon these paths. Some paths are relative to the current UIKit. See UIKit configuration for more info. Note the patternlabFiles which help create the front end styleguide. Note also the intentional repetition of the nested structure, made this way for maximum flexibility. These are unlikely to change unless you customize your environment or write custom UIKits.

default :

  "paths": {
"source": {
"root": "./source/",
"patterns": "./source/_patterns/",
"data": "./source/_data/",
"meta": "./source/_meta/",
"annotations": "./source/_annotations/",
"styleguide": "dist/",
"patternlabFiles": {
"general-header": "views/partials/general-header.mustache",
"general-footer": "views/partials/general-footer.mustache",
"patternSection": "views/partials/patternSection.mustache",
"patternSectionSubgroup": "views/partials/patternSectionSubgroup.mustache",
"viewall": "views/viewall.mustache"
"js": "./source/js",
"images": "./source/images",
"fonts": "./source/fonts",
"css": "./source/css"
"public": {
"root": "public/",
"patterns": "public/patterns/",
"data": "public/styleguide/data/",
"annotations": "public/annotations/",
"styleguide": "public/styleguide/",
"js": "public/js",
"images": "public/images",
"fonts": "public/fonts",
"css": "public/css"


Sets the panel name and language for the code tab on the styleguide. Since this only accepts one value, this is a place where mixed pattern trees (different PatternEngines in the same instance of Pattern Lab) does not quite work.

default: mustache


An engine is a wrapper around a templating library like Handlebars, Twig or others. An engine package is the bridge between Pattern Lab and the standalone NPM package supporting the templating language.

engines accepts an map of Engine objects. The mandatory properties for each Pattern Lab engine are:

  • package: the NodeJS package name. Add the package of the engine as a dependency in package.json before you configure it here.
  • fileExtensions: list of pattern file extensions which will be handled by this pattern engine.

Other engine specific configuration options can be added and will be passed to the pattern engine at loading time. See the NPM package documentation for the properties each pattern engine supports.


  "engines": {
"handlebars": {
"package": "@pattern-lab/engine-handlebars",
"fileExtensions": [
"extend": "helpers/*.js"

Configuring the engines in the config file was introduced in v5.14. The fallback lookup mode by scanning the node_modules folder is deprecated and will be removed in Pattern Lab v7.


See the Pattern State Documentation


"patternStateCascade": ["inprogress", "inreview", "complete"],


Sets the location that any export operations should output files to. This may be a relative or absolute path.

default: ./pattern_exports/


Sets an array of patterns (using the short-hand pattern-include syntax) to be exported after a build.

For example, to export the navigation, header, and footer, one might do:

"patternExportPatternPartials": ["molecules-primary-nav", "organisms-footer", "organisms-header"],

default: []


Used to override the merge behavior of pattern variants. For more information see The Pseudo-Pattern File Data.

  • true will merge arrays of the pattern and pseudo-pattern with lodash merge
  • false will override arrays from the pattern with pseudo-patterns arrays
"patternMergeVariantArrays": true,

default: true | undefined


Set to true to enable adding a wrapper div with css class(es) around a pattern.
For more information see Pattern Wrap Classes.

"patternWrapClassesEnable": false,

default: false


Configure your class keys for "patternWrapClassesEnable": true.
For more information see Pattern Wrap Classes.

"patternWrapClassesKey": ['theme-class'],

default: []


Used to activate rendering flat patterns on view all pages and generate view all pages if only flat patterns are available

  • true will render flat patterns on view all pages
  • false will make flat patterns available only in the menu
"renderFlatPatternsOnViewAllPages": true,

default: false | undefined


Sets live-server options:

keyexample valuedescription
port8181Set the server port. Defaults to 8080.
host""Set the address to bind to. Defaults to or process.env.IP.
root"/public"Set root directory that's being served. Defaults to cwd.
openfalseWhen false, it won't load your browser by default.
ignore'scss,my/templates'Live-Reload: Comma-separated string for paths to ignore from watching for changes in the filesystem. Use with caution: This would overwrite the default 'public' path, that's highly recommended to get ignored.
ignorePatternLive-Reload: Regular expression for ignoring specific file types from being watched for changes in the filesystem.
file"index.html"When set, serve this file for every 404 (useful for single-page applications).
wait100Waits for all changes, before reloading. Defaults to 0 sec.
mount[['/components', './node_modules']]Mount a directory to a route.
logLevel20 = errors only, 1 = some, 2 = lots
middleware[function(req, res, next) { next(); }]Takes an array of Connect-compatible middleware that are injected into the server middleware stack
https'ssl/ssl.js'adding the path to a configuration module for HTTPS dev servers, see detailed explanation on therunning patternlab page


"serverOptions": {
"wait": 1000


Starterkits by convention house their files within the dist/ directory. Should someone ever wish to change this, this key is available.


"starterkitSubDir": "dist",


Sets whole pattern types to be excluded from the "All" patterns page on the styleguide. This is useful to decrease initial load of the styleguide. For example, to exlude all patterns under templates and pages, add the following:

"styleGuideExcludes": [

These template and page patterns would still be accessible via navigation.

default: []


Sets the theme options for the styleguide. There are five options:

  • "color"
  • "density"
  • "layout"
  • "noViewAll" (optional)
  • "logo" (optional)

Available values are:

"theme" : {
"color" : "dark" | "light",
"density" : "compact" | "cozy" | "comfortable",
"layout" : "horizontal" | "vertical",
"noViewAll" : true | false,
"logo": {
"text": "Pattern Lab",
"altText": "Pattern Lab Logo",
"url": "./",
"srcLight": "styleguide/images/pattern-lab-logo--on-light.svg",
"srcDark": "styleguide/images/pattern-lab-logo--on-dark.svg",
"width": "187",
"height": "185"

See the initial release notes for the theme feature for example output on "color", 'density" and "layout".

"noViewAll" provides the possibility to hide the "View All" pages and links within the navigation.

And "logo" lets you finetune the different aspects of the logo displayed on the left top corner of the styleguide.


"theme" : {
"color" : "dark",
"density" : "compact",
"layout" : "horizontal"

transformedAssetTypes (optional)permalink

Prevent specific filetypes being copied from your source to your public folder like e.g. CSS preprocessor source files (.scss), you could specify those within an array of your pattern lab config:

"transformedAssetTypes": [

default: []


Introduced in Pattern Lab Node v3, UIKits are a new term in the Pattern Lab Ecosystem. They are an evolution of the original Styleguidekit pattern which separated front-end templates from front-end assets like stylesheets and code. The existing styleguidekit-assets-default and styleguidekit-mustache-default have merged into uikit-workshop.

uikits accepts an array of UIKit objects, shipping with the one above.

  • name: the name of the UIKit
  • package: the NodeJS package name. This property was introduced in version 5.13 to allow for a uikit package to be used multiple times with different names. Add the package as a dependency in package.json before you configure it here.
  • outputDir where to output this UIKit relative to the current root. By leaving this empty we retain the existing Pattern Lab 2.X behavior, outputting to <project_root>/public. If you had multiple UIKits, however, you would provide different values, such as:
  "uikits": [
"name": "uikit-workshop",
"package": "@pattern-lab/uikit-workshop",
"outputDir": "workshop",
"name": "uikit-storefront",
"package": "@pattern-lab/uikit-storefront",
"outputDir": "storefront",
  • enabled: quickly turn on or off the building of this UIKit
  • excludedPatternStates: tell Pattern Lab not to include patterns with these states in this UIKit's output
  • excludedTags: tell Pattern Lab not to include patterns with these tags in this UIKit's output

Important details:

  • the default paths.source object paths within patternlab-config.json are now relative to the current UIKit. See the structure of uikit-workshop for more info
  • the default paths.public object paths within patternlab-config.json are now relative to the current UIKit's outputDir. Absolute paths will no longer work. Someone could test putting an absolute path in a UIKit outputDir property and see what happens I suppose.
  • dependencyGraph.json has moved to the project root rather than public/ as we should only retain one
  • The lookup of the uikit by name is deprecated and will be removed in v7. The user will be notified of it. If the package property isn't defined, there is a default fallback lookup strategy where the value of name is tried as:
    • <name>
    • uikit-<name>
    • @pattern-lab/<name>
    • @pattern-lab/uikit-<name>


  "uikits": [
"name": "uikit-workshop",
"package": "@pattern-lab/uikit-workshop",
"outputDir": "",
"enabled": true,
"excludedPatternStates": [],
"excludedTags": []

Pattern Engine-Twigpermalink


Adding custom TwingExtensions to engine-twig via setting a filename in

"engine": {
"twig": {
"loadExtensionFile": ""