Designing WordPress themes the old-fashioned way is time-consuming and error-prone. Automating the build process allows us to integrate best practices into our workflow while saving time. This project is a starter kit for developing highly optimized WordPress themes with Gulp, npm, and Sass, among other tools. This is not meant to be a starter theme or framework (although I have included a minimum viable theme to demonstrate some of the possibilities). It is, instead, a kind of project scaffolding and example workflow for modern and efficient WordPress theme development.

The latest version of this starter kit features a modular Gulp file design inspired by Dan Tello's excellent gulp-starter. Configuration is isolated from the tasks themselves to make it easier to change paths and modify settings. This approach is slightly more complicated than what I originally outlined on my blog but also far more powerful. Live local development is now facilitated by your choice of BrowserSync or LiveReload (the default choice).

Why use this project instead of any of the alternatives? A few advantages:

• It doesn't try and do too much.
• You should be able to easily drop your own theme into the src folder and start hacking without much additional setup.
• Documentation and comments in the code assume a novice level of understanding.
• Builds on existing WordPress and Gulp best practices without doing anything too crazy.
• Will save you a ton of time and help you make better, more readily optimized themes once you learn how it all works.

If you're already up and running with most of the usual Node ecosystem tools this starter kit won't require much additional effort.

• Install npm.
• Install Gulp: npm install gulp -g.
• Download or clone this repo: git clone https://github.com/synapticism/wordpress-gulp-starter-kit.git.

• Install Bower: npm install bower -g (helps manage front-end dependencies, particularly CSS libraries and such; see below for more info).
• Install Composer (a PHP package manager, not really necessary).
• Install Sass (only if the built-in, default libsass compiler isn't good enough for your needs): gem install sass (requires Ruby).

• Edit gulpconfig.js and, at the very least, change the project variable to match the name of your theme. If you like the way this workflow is setup you shouldn't need to edit any of the files under gulpfile.js/tasks just yet.
• Install all dependencies by running npm install. This will fetch all dependencies listed in package.json (which includes front-end JavaScript packages and back-end tools like Gulp plugins and BrowserSync).
• BrowserSync setup: assuming you have a local development environment setup all you should need to do is enter the URL into the proxy setting in gulpconfig.js. Why use BrowserSync? It's fast, awesome, and allows for simultaneous responsive development across multiple devices.
• LiveReload setup: install a browser extension for Chrome or Firefox. Why use LiveReload? It does the job without complications or additional setup after the extension is installed.
• Run gulp and start hacking!

Previously this project shipped without a working theme included. I figured that with all the great starter themes out there (for instance, _s, Roots, and Bones) it wouldn't be hard to drop one in and start theming. I don't personally use any of these so I was a little surprised to discover how tricky this can be. Starter themes, despite their "bare bones" reputation, are often bulky and opinionated. Some even ship with their own build processes already in place!

It seems there is a need for what I'd call a minimum viable theme: a truly bare bones WordPress starter theme featuring only the essentials to get up and running, something that you can assess at a glance. For the purposes of this project I have created such a theme, tentatively named voidx. It isn't pretty and isn't up to WordPress standards but it works well enough to show off some of the power of this workflow. Feel free to play with or discard it as you wish. All files under src can be replaced by your own files, you just have to be sure to wire things up properly in the gulpconfig.js file if you swap in your own stuff.

There are two components worth a closer look, however:

• The script variable and enqueuing functions in src/inc/assets.php; these are tightly coupled with the output of the build process.
• The theme configuration pattern described in functions.php and functions-config-defaults.php.

Whether you use anything from this built-in theme is entirely up to you. If you prefer to start working with your own theme just drop it in. You may need to go into gulpconfig.js and modify paths and glob matching patterns but this is designed to be fairly easy and straight-forward with lots of comments to point you in the right direction.

This starter kit uses src, build, and dist folders to organize theme development:

• src: this directory contains the raw material for your theme: templates (src/), PHP includes (src/inc), language files (src/languages), styles (src/scss), scripts (src/js), and images (anywhere under src/). Only edit files in this directory!
• build: generated by Gulp, this is a working copy of your theme for use in development and testing. Symlink build to your wp-content/themes directory for local development and testing (e.g. if your theme is in ~/dev/themes/my-theme and your local copy of WordPress is installed in ~/dev/localhost/wp you'll want to run ln -s ~/dev/themes/my-theme/build ~/dev/localhost/wp/wp-content/themes/my-theme).
• dist: short for distribution, this will be the final, polished copy of your theme for production. You will need to manually run gulp dist to create a new distribution. You can also symlink this directory for a final round of testing; just keep in mind that your theme will now be in dist/[project], where [project] is the setting at the top of the Gulp configuration. This project folder is what you will want to deploy to production. (No more weird junk in your themes. Hooray!)

Note: both the build and dist directories are disposable and can be regenerated from the contents of src. You aren't likely to want to edit files in this folders but you may want to open them up to diagnose issues with the build process itself.

Gulp is an extremely powerful tool for automating tasks from the command line. If you're new to Gulp but coming from a WordPress background I recommend reading tutorials by Matt Banks and Mark Goodyear. I also learned a lot from a post by Dan Trello (and have integrated much of his approach into this project) but it might be a bit more opaque for newcomers.

To get started try running gulp from the command line. This fires gulpfile.js/index.js and should build a working copy of the included theme. The other command you will use from time to time is gulp dist, which builds a distribution copy.

You might also find a need for gulp setup which runs one-off setup tasks (which is also triggered by gulp dist). In the default installation this setup task only copies normalize.css to src/scss so it can be imported like a native SCSS file. This task is also run after npm install completes.

Configuration is handled by a single file: gulpconfig.js. If you leave the directory structure intact there won't be too much that needs changing here but I can think of two non-obvious components you might want to modify or at least look at:

• BrowserSync settings: if you are developing on a local web server you will want to enter the URL into browsersync.proxy and then change watch.watcher to browsersync to take it for a test drive. You'll know it's working when you run gulp and a new browser opens with a live copy of your web site. Make changes to any of the Sass files and they should be shown on the page almost immediately. Of course, BrowserSync really shines when you connect a mobile device to your development server, but for that you're on your own ;)
• Script settings: draw your attention to scripts.bundles and scripts.chunks. This feature is essentially a poor man's Browserify or Webpack. By defining different "chunks" (script files that combine to provide a particular feature) and "bundles" (chunks that combine to provide feature sets) you can generate an assortment of files that can be efficiently and intelligently loaded through your WordPress theme. This approach has its limitations, of course, particularly when dependencies are shared between scripts, but it should be of use to many WordPress theme developers.

Interested in adding new Gulp plugins to your build system? A full tutorial is out of scope for this project but it really shouldn't be all that hard to figure out. In brief, install a plugin with npm install [package] --save-dev, require it in a suitable task file, add something to the configuration file if needed, and drop it into the pipeline somewhere. Some types of plugin are particularly easy to add, for instance anything listed on the postcss.parts web site (install, require, and add to the processor variable in ./gulpfile.js/tasks/styles.js).

npm is great for working with packages of all kinds (front-end or back-end) and is increasingly becoming the package manager of choice. Previously this starter kit emphasized the use of Bower to retrieve and manage front-end dependencies but nowadays my personal preference is to use npm, mostly because it's way easier to update dependencies than Bower using tools like npm-check-updates.

• Find new packages with npm search [package].
• Install new packages with: npm install [package] --save-dev.
• A general rule-of-thumb: if you can find it there just use npm.

A few handy tips from the Bower documentation:

• Search for packages with bower search [package] or browse the Bower web interface.
• Install new packages with: bower install [package] --save-dev.
• Remove packages by deleting a line from bower.json and then run bower prune.
• Clean the cache with bower cache clean (occasionally needed when things start getting weird).

• This package now supports either gulp-ruby-sass (which requires the original Ruby implementation of Sass) or gulp-sass (based on the newer, experimental, and faster libsass, now active by default). Switch styles.compiler in the configuration file as needed! For reference: Sass compatibility table.
• Sass files can be found in /src/scss. Gulp will not process Sass partials beginning with _; these need to be explicitly imported (see style.scss for an example). On the other hand, if you want to output any other CSS files just drop the underscore e.g. editor-style.scss.
• Packages installed with Bower or npm are in the path by default so you can @import Sass files directly, as seen in style.scss.
• The build folder is provisioned with regular versions of all stylesheets but dist only contains minified versions for production.
• This starter kit ships with Normalize.css (imported into the src/scss directory using gulp setup; you might also like to explore the use of normalize-scss for your project).
• Compass is not included as Autoprefixer, a PostCSS plugin, eliminates the need for vendor prefixing (which is what most Sass frameworks focus on these days). Instead I have included Scut, a minimalist library of useful Sass mixins and functions for the post-vendor prefixing era. This is easily removed if you're not interested in using it.
• Sourcemaps are generated by gulp-sourcemaps to make debugging stylesheets a snap.

Images are copied from wherever they are in src to the same location under build. They are only optimized when running gulp dist as this operation is resource-intensive.

Like images, PHP (and language) files can go anywhere under src and will be copied to build and dist while preserving directory structure.

Let's say you run across a cool project like Headroom.js and decide you'd like to try it out. Here's how you would do that with the tools and workflow outlined in this repo:

• npm install headroom.js --save-dev. This will save the package to the devDependencies field of your package.json file.
• Look up the path to the script and add the appropriate entries to scripts.bundles and scripts.chunks in gulpconfig.js. The key name of scripts.bundles should match $script_name (below). Since this script is meant to be loaded on every page it is safe to bundle it with the core script.
• To make this script optional requires a bit more work:
  • Add an option to functions-config-defaults.php: defined( 'VOIDX_SCRIPTS_HEADROOM' ) || define( 'VOIDX_SCRIPTS_HEADROOM', true );.
  • Add the switch to inc/assets.php: if ( VOIDX_SCRIPTS_HEADROOM ) : $script_name .= '-hr';.
  • Add an option to scss/_config.scss to allow for the styling to be turned on or off: $plugin-headroom: true;.
  • Add the necessary styling to scss/_plugins.scss wrapped in a conditional check: @if ($plugin-headroom) { // Style }.
  • Create an additional script at src/js/headroom.js to invoke the main script (code to follow).

// Invoke Headroom.js
;(function($){
  $(function(){
    $("#wrap-header").headroom({ offset: 60 });
  });
}(jQuery));

That's all there is to it. Now this script can be switched on or off in two configuration files. WordPress will automatically load the correct script bundle for all JavaScript-based functionality (rather than loading lots of little scripts for each feature).

Things can and will go wrong when working with new tools but there are a few simple things you can do to avoid the worst of it:

• Make sure everything is up to date, particularly this package, npm, node, Bower, etc.
• If you're getting weird errors you can't figure out try deleting node_modules and running npm install.
• You might also have some luck cleaning the cache for both npm and Bower, both of which respond to the clean cache command, or try npm prune && npm install.

• Yeoman generator (open issue; some help here would be awesome since I don't personally use Yeoman).
• Better error handling (waiting for Gulp 4).
• Reduce unnecessary wrapper plugins.
• RTL support with gulp-rtlcss?
• Explore using Gulp for I18n (a quick scan revealed nothing obviously useful).
• Browserify integration? The existing bundles/chunks system is very DIY and non-standard. Feedback welcome.
• More good ideas from Gulp recipes.

Feature requests and bug reports welcome; open an issue! Please note that I intend to reign in scope creep on this project :)

Like the approach but prefer something more mature, sophisticated, and opinionated? Check out Sage and Bedrock from Roots. Interested in another more stripped-down approach? Have a look at gulp-wp-theme.

The initial version of this repo featured a gulpfile.js adapted from Matt Banks. Additional credit is due to Mark Goodyear. The current version is largely based on Dan Tello's excellent gulp-starter. The theme templates included in this project ultimately descend from Twenty Twelve.

Licensed under the GPL 3.0. You are encouraged to link back to my web site, development blog, and/or this GitHub repository if you find this at all useful.