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1.0.6 • Public • Published


Wyldstyle is a javascript CLI script that reads your markup and writes utility classes for you.

It's inspired by Tachyons and Atomic CSS where, your markup has reusable classes to prevent developers from writing too many styles.

Wyldstyle has both a compiler and a watcher. Running a watcher, you can just continuously code on the markup while the utility file is generated every time your file has been saved.


Wyldstyle extracts out the utilities you've set, runs them through Emmet and writes them to a file. In this preview, we'll show the support for breakpoints, hover states, and variables.


<section class="article-list [ u-d:fx u-jc:sb u-m:0a ]">
  <article class="article [ u-p:1r u-mb:1.5r u-mb:2r@l ]">
    <h1 class="article__title [ u-tt:u u-td:n u-c:$link-color u-c:$link-color-hover@h ]"><a href="#">Article Title</a></h1>
     <p class="article__excerpt [ u-lh:1.5 ]">Lorem ipsum dolor sit amet, consectetur adipiscing elit. Ut sed tortor mattis, blandit nisi tincidunt, ultrices turpis.</p>

Generated CSS

.u-c\:\$link-color { color: $link-color; }
.u-c\:\$link-color-hover\@h:hover { color: $link-color-hover; }
.u-d\:fx { display: flex; }
.u-jc\:sb { justify-content: space-between; }
.u-lh\:1\.5 { line-height: 1.5; }
.u-m\:0a { margin: 0 auto; }
.u-mb\:1\.5r { margin-bottom: 1.5rem; }
.u-p\:1r { padding: 1rem; }
.u-td\:n { text-decoration: none; }
.u-tt\:u { text-transform: uppercase; }
@media (min-width: 768px) {
@media (min-width: 1024px) {
  .u-mb\:2r\@{ margin-bottom: 2rem; }
@media (min-width: 1200px) {

The utility classes are prefixed with u- (which can be changed in the config file [See Configuring Emmet]). All the other utilities follow Emmet's conventions.

Here's a link to the Emmet Cheatsheet!

Getting Started

This package requires the use of ES6. node >= 6.*

We need to install the wyldstyle command line tool from npm.

npm install wyldstyle --save-dev

NOTE: You can also install it globally but we prefer using npm scripts so everything we need is explicitly stated in our package.json files.

Next up is to tell wyldstyle to watch our markup file for changes and write them to a stylesheet

wyldstyle index.html article.html --output css/theme.css --watch

Usage and Configuration

Command Line

wyldstyle [target directory or file] [--flags] [--output] [--watch]

Wyldstyle has multiple ways in passing arguments but it's flexibility and advanced configuration comes in a wyldstyle.json file.

Before we run through that, let's first look at the command line arguments since command line flags are enough for most.

By default, wyldstyle just runs through all the files once and writes them to a file.

Flags Alias Multiple? Description
--output -o No The file where wyldstyle will write the utilities on.
--ignore -i Yes File or directory to ignore when watching the directories.
--watch -w No Start watching the directories provided

Config File

Using a config file on the otherhand makes it much manageable when woring on a project rather than just a prototype. When using the config file, we write up a wyldstyle.json file in the project root.

In the cofiguration file, we can set custom breakpoints and configure emmet as well!

Now, our config file should look something like this:

  "breakpoints": {
    "m":  "768px",
    "l":  "1024px",
    "xl": "1200px"
  "directory": ["assets/js", "templates"],
  "output": "assets/scss/_utilities.scss",
  "emmet": {
    "syntax": "scss",
    "preferences": {
      "caniuse.enabled": false,
      "css.autoInsertVendorPrefixes": false
    "snippets": {
      "m:0a": "margin: 0 auto;"

Take note that any command line argument will override the config file.


Breakpoints are configurable. The key, (m, l, xl) can actually be interchanged to what you prefer. The config we provide as an example stands for medium, large, extra large.

An example is, you can change it up m, t, d, r, to stand for mobile, tablet, desktop, and retina. It should immediately take place when parsing the markup u-p:3p@r.

Configuring Emmet

The emmet config actually just uses the direct emmet npm api. There's documentation for both the preferences and the snippets which you can look up here:

As a quick start guide, here are the most common preferences we use:

Preference Default Description
caniuse.enabled true This prefixes the attributes like display: -webkit-flex
css.autoInsertVendorPrefixes true Emmet runs an autoprefixer for css classes

On How We Use It


On our end, we disable caniuse.enabled and css.autoInsertVendorPrefixes by default since we use pre-processors in project development and rely on post-css to generate the prefixes rather than inserting them directly on our stylesheets. Though this is purely for cleanliness' sake.


When it comes to development, we usually create a dedicated file called _utilities.scss file where wyldstyle writes up our utilities and we import it to the master theme file.


For the breakpoints, we prefer creating a map that holds our variables and reference the function to call the breakpoint instead. Just for maintainability and fluency.


$breakpoints: (
    tablet:  1rem,
    desktop: 2rem,
    retina:  3rem
@function breakpoint ($breakpoint) {
    @return map-get($breakpoints, $breakpoint);


    "breakpoints": {
        "m": "breakpoint(tablet)",
        "l": "breakpoint(desktop)",
        "xl": "breakpoint(retina)"

Roadmap and Enhancements


Major Codebase Refactor

When wyldstyle was first developed, midway of development, it ended up having a lot of hacky solutions for the breakpoints and the compilation. And even though this version has a high probability of being the same, the aim is to have a much more maintainable code base that I wouldn't really want to rewrite after looking at it for a second time. Hopefully.


Hover States

Implement the @h postfix for hover states. u-c:$font-color-hover@h and be parsed to .u-c\:\$font-color-hover\@h:hover { color: $font-color-hover; }

Custom Dynamic Snippets

The current support for snippets are hardcoded values. We want to start supporting custom snippets with a bit more variability to it.

    "m:0a": "margin: 0 auto;"

Currently, I'm not really sure how to implement a snippet where the stylesheet attribute value is customizable.

    "grid:3": "flex:basis: calc((100%/{value}) - 2);"


Style Guide

Add support for a forced style guide or format in the config file.

    "format": {
        "padding":   ["0.5r", "1r", "1.5r"],
        "margin":    ["0.5r", "1r", "1.5r"],
        "font-size": ["1r"],
        "color":     ["$black", "$red"]

This is just better enforcement for large scale team projects to avoid cutting corners.

I'm thinking a notification should be triggered, or a callback should be triggered when compiling when a non-allowed value has been paired with the attribute. Just in case the developer ends up forgetting about the style guide.

Extension Support

It's planned to support a more extensible architecture to provide different approaches on usage for Wyldstyle. Of course, this is tailored on how we develop on the frontend but by allowing an extension/plugin architecture, it may be possible to hook into pre-expansion, post-expansion and post-compile events to do added processing.

In the long run, we want to export the style-guide, hover states, breakpoints, and even the snippets into the extension to just have a proof of concept on hand.

By implementing this we may even add another flag for the command line tool for transformations.

wyldstyle index.html --watch --output css/utilities.css --transform autoprefixer

No Particular Version

Javascript API Configurability

Now this is something I particularly want to implement correctly but I don't have any shred of idea how to.

This comes in tied in with most of the features for the definite versions since most of the configuration needs to be done language first.

wyldstyle(directories, {
    events: {
        preCompile: function (abbreviation) {
            return abbreviation;
        postCompile: function (style) {
            return style;


npm i wyldstyle

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