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About the Node Version of Pattern Lab

The Node version of Pattern Lab is, at its core, a static site generator. It combines platform-agnostic assets, like the Mustache-based patterns, the JavaScript-based viewer, and the self-contained webserver, with a Node-based "builder" that transforms and dynamically builds the Pattern Lab site.

This repository contains the vanilla builder logic, grunt and gulp configurations, and some sample template/css/data to illustrate the power and flexibility of the tool.

Core Team


Make sure Node and npm are installed. A great guide can be found here:


  • Download the latest release of patternlab-node from Github
  • Via npm, run npm install patternlab-node (Note this will auto install the grunt version currently. see below)
  • NOTE Node version 4.X and 5.X have tentative support, citing a lot of Windows issues, including mine. Upgrade node at your own risk until otherwise stated. I've tried to catalog some issues and troubleshooting steps on the wiki.

Troubleshooting Installs

Make sure you are running your terminal/command line session as administrator. This could mean sudo, or opening the window with a right-click option.

Choose Your Adventure! Now Vanilla, Grunt & Gulp

This repository ships with two package.json files, a Gruntfile.js, and a gulpfile.js. The default is grunt currently. The core builder is not dependent on either.

Getting Started - Grunt

To run patternlab-node using grunt, do the following in the directory you downloaded and extracted the zipped release:

  1. Run npm install from the command line
  2. Optionally, delete package.gulp.json, gulpfile.js, and builder/patternlab_gulp.js files if you are certain you don't need it.
  • Not deleting builder/patternlab_gulp.js may cause a harmless error when running grunt. Delete it.
  1. Run grunt or grunt serve from the command line

This creates all patterns, the styleguide, and the pattern lab site. It's strongly recommended to run grunt serve to have BrowserSync spin up and serve the files to you.

Getting Started - Gulp

To run patternlab-node using gulp, you need to swap out the default grunt configuration. Do the following in the directory you downloaded and extracted the zipped release:

  1. Rename package.json to package.grunt.json or delete it if you don't intend on going back
  2. Rename package.gulp.json to package.json
  3. Run npm install from the command line
  4. Run gulp or gulp serve from the command line

This creates all patterns, the styleguide, and the pattern lab site. It's strongly recommended to run gulp serve to have BrowserSync spin up and serve the files to you.

There and Back Again, or Switching Between Grunt and Gulp

It's not expected to toggle between the two build systems, but for those migrating between the two configs, here's some general guidelines:

  • Make sure your package.json files are correct per the Getting Started sections.
  • Run npm cache clear before installation
  • Delete the contents of ./node_modules if you want a cleaner installation.
  • Regarding speed, Gulp is faster. BrowserSync takes a bit longer than the old static server to spin up, but its capabilities far outweigh the startup cost.


You can find instructions on how to upgrade from version to version of Pattern Lab Node here:

Command Line Interface

The following are grunt/gulp task arguments you may execute:


With no arguments, patternlab runs the full builder, compiling patterns, and constructing the front-end site.


Compile the patterns only, outputting to ./public/patterns


Retrieve the version of patternlab-node you have installed


Get more information about patternlab-node, pattern lab in general, and where to report issues.

Further Configuration

Watching Changes

To have patternlab-node watch for changes to either a mustache template, data, or stylesheets, run grunt|gulp watch or grunt|gulp serve. The Gruntfile|Gulpfile governs what is watched. It should be easy to add scss or whatever preprocessor you fancy.

Configurable Paths

Pattern Lab Node ships with a particular source and public workflow intended to separate the code you work on with the code generated for consumption elsewhere. If you wish to change any paths, you may do so within config.json. The contents are here:

"paths" : {
    "source" : {
      "root": "./source/",
      "patterns" : "./source/_patterns/",
      "data" : "./source/_data/",
      "styleguide" : "./core/styleguide/",
      "patternlabFiles" : "./source/_patternlab-files/",
      "js" : "./source/js",
      "images" : "./source/images",
      "fonts" : "./source/fonts",
      "css" : "./source/css/"
    "public" : {
      "root" : "./public/",
      "patterns" : "./public/patterns/",
      "data" : "./public/data/",
      "styleguide" : "./public/styleguide/",
      "js" : "./public/js",
      "images" : "./public/images",
      "fonts" : "./public/fonts",
      "css" : "./public/css"

Note the intentional repitition of the nested structure, made this way for maximum flexibility. Relative paths are default but absolute paths should work too. You may also use these paths within Grunt or Gulp files by referring to the paths() object.

Nav Bar Controls

If you don't have a need for some of the nav-bar tools in the Pattern Lab frontend, you can turn them off in config.json.

The current selection is as follows.

"ishControlsVisible": {
	"s": true,
	"m": true,
	"l": true,
	"full": true,
	"random": true,
	"disco": true,
	"hay": true,
	"mqs": false,
	"find": false,
	"views-all": true,
	"views-annotations": true,
	"views-code": true,
	"views-new": true,
	"tools-all": true,
	"tools-follow": false,
	"tools-reload": false,
	"tools-shortcuts": false,
	"tools-docs": true
Pattern States

You can set the state of a pattern by including it in config.json too. The out of the box styles are in progress (orange), in review (yellow), and complete (green). Pattern states should be lowercase and use hyphens where spaces are present.

"patternStates": {
	"colors" : "inprogress",
	"fonts" : "inreview",
	"three-up" : "complete"
Pattern Export

config.json also has two properties that work together to export completed patterns for use in a production environment. Provide an array of keys and an output directory. Pattern Lab doesn't ship with any pattern export keys, but the default directory is "./pattern_exports/" created inside the install directory.

"patternExportKeys": ["molecules-primary-nav", "organisms-header", "organisms-header"],
"patternExportDirectory": "./pattern_exports/"

Coupled with exported css (much easier to extract with existing tools like grunt-contrib-copy), pattern export can help to maintain the relevancy of the design system by directly placing partials in a directory of your choosing.


If your instance of Pattern Lab lives in a subdirectory of your server, for instance on github pages (ex:, then add the baseurl here. The baseurl is everything after the hostname - ie: patterns-demo

"baseurl" : "/patterns-demo"

Default: blank

excluding patterns

If you'd like to exclude an individual pattern you can do so by prepending the filename with an underscore, like: _filename.mustache

You can also exclude complete directories by prepending the directory name with an underscore, like: /_experiment/...

Style Guide Excludes

Exclude whole pattern types from the "All patterns" styleguide by adding entries to config.json. This is quite useful to make speedier. Pattern Lab Node ships with the following:

"styleGuideExcludes": [
Debug Mode

patternlab.json is a file created for debugging purposes. Set debug to true in .config.json to see all the secrets.

Server & BrowserSync

Running grunt serve or gulp serve will compile the Pattern Lab frontend and host it by default on http://localhost:3000 via BrowserSync. After it starts, templates, data.json, and scss/css changes in your source code will be automatically injected into the page.

You'll notice that if you have this open across different browsers, we do our best to keep the frontend in sync, but there is a known issue with synced navigation using the main menu.


A roadmap exists for Pattern Lab Node. Check it out here. The Node version of Pattern Lab is maintained by @bmuenzenmeyer and contributors. Pull requests welcome, but please take a moment to read the guidelines.

Dave Olsen has also published the specification for Pattern Lab ports. Development will be oriented toward compliance with this as the spec and the port mature together. Post v1 work will focus on other pattern engines and a plugin architecture.

Advanced Pattern Library Features

Pattern Parameters

Pattern parameters are a simple mechanism for replacing Mustache variables via attributes on a pattern partial tag rather than having to use a pattern-specific json file. They are especially useful when you want to supply distinct values for Mustache variables in a specific pattern partial instance that may be included multiple times in a molecule, template, or page.

The basic syntax is this:

{{> molecules-single-comment(description: 'A life is like a garden. Perfect moments can be had, but not preserved, except in memory.') }}

The attributes listed in the pattern parameters should match Mustache variable names in your pattern. The values listed for each attribute will replace the Mustache variables. Again, pattern parameters are a simple find and replace of Mustache variables with the supplied values.

Pattern parameters do not currently support the following:

  • sub-lists (e.g. iteration of a section),
  • and the use of long strings of text can be unwieldy
  • nested properties within the parameter data, such as {{> molecules-single-comment( 'baz') }}

You can read the full documentation on pattern parameters here: Using Pattern Parameters

Pattern Style Modifiers

Style Modifiers allow you to create a base pattern that you can easily modify by adding a class name to the pattern partial. Read more about them here, including support with pattern parameters. Below is the gist.

The basic syntax is this:

{{> atoms-message:error }}

This works by using a reserved mustache variable of sorts called {{ styleModifier }} applied to the atoms-message mustache file itself:

<div class="message {{ styleModifier }}">{{ message }}</div>

Once rendered, it looks like this:

    <div class="message error"></div>

You may also specify multiple classes using a pipe character (|).

{{> atoms-message:error|is-on }}

Pseudo-patterns are meant to give developers the ability to build multiple and unique rendered patterns off of one base pattern and its mark-up while giving them control over the data that is injected into the base pattern. This feature is especially useful when developing template- and page-style patterns.

Pseudo-patterns are, essentially, the pattern-specific JSON files that would accompany a pattern. Rather than require a Mustache pattern, though, pseudo-patterns are hinted so a developer can reference a shared pattern. The basic syntax:


The tilde, ~, and JSON extension denotes that this is a pseudo-pattern. patternName is the parent pattern that will be used when rendering the pseudo-pattern. patternName and pseudoPatternName are combined when adding the pseudo-pattern to the navigation.

The JSON file itself works exactly like the pattern-specific JSON file. It has the added benefit that the pseudo-pattern will also import any values from the parent pattern's pattern-specific JSON file. Here is an example (which ships with the package) where we want to show an emergency notification on our homepage template. Our 03-templates/ directory looks like this:


Our 00-homepage.mustache template might look like this:

<div id="main-container">
    {{# emergency }}
        <div class="emergency">Oh Noes! Emergency!</div>
    {{/ emergency }}
    { ...a bunch of other content... }

If our _data.json file doesn't give a value for emergency that section will never show up when 00-homepage.mustache is rendered.

We want to show both the regular and emergency states of the homepage but we don't want to duplicate the entire 00-homepage.mustache template. That would be a maintenance nightmare. So let's add our pseudo-pattern:


In our pseudo-pattern, 00-homepage~emergency.json, we add our emergency attribute:

    "emergency": true

Now when we generate our site we'll have our homepage template rendered twice. Once as the regular template and once as a pseudo-pattern showing the emergency section. Note that the pseudo-pattern will show up in our navigation as Homepage Emergency.

Pattern Linking

You can build patterns that link to one another to help simulate using a real website. This is especially useful when working with the Pages and Templates pattern types. The basic format is:

{{ link.pattern-name }}

For example, if you wanted to add a link to the home page template from your blog template you could write the following:

<a href="{{ link.templates-homepage }}">Home</a>

This would compile to:

<a href="/patterns/templates-homepage/templates-homepage.html">Home</a>

As you can see, it's a much easier way of linking patterns to one another.


Working with Patterns

(The following documentation is built for the PHP version of Pattern Lab, but most applies to the node version too. If you find omissions or mistakes please open an issue.)

Patterns are the core element of Pattern Lab. Understanding how they work is the key to getting the most out of the system. Patterns use Mustache so please read Mustache's docs as well.

Creating & Working With Dynamic Data for a Pattern

The Node version of Pattern Lab utilizes Mustache as the template language for patterns. In addition to allowing for the inclusion of one pattern within another it also gives pattern developers the ability to include variables. This means that attributes like image sources can be centralized in one file for easy modification across one or more patterns. The Node version of Pattern Lab uses a JSON file, source/_data/data.json, to centralize many of these attributes.

Using Pattern Lab's Advanced Features

By default, the Pattern Lab assets can be manually generated and the Pattern Lab site manually refreshed but who wants to waste time doing that? Here are some ways that Pattern Lab can make your development workflow a little smoother:

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