Skip to main contentGatsby theme Carbon


Use this guide to contribute to the theme. We’ll show you how to get the development environment set up as quickly as possible so you can start contributing.

Project setup

  1. Go to gatsby-theme-carbon and click the Fork button in the top-right corner.

  2. After it’s finished, click on the Clone or Download button and copy the contents.

  3. In your terminal, clone the repo into your directory of choice

git clone [PASTE_URL_HERE]
cd gatsby-theme-carbon
  1. When you clone your forked repo the origin is set to your fork by default. You’ll want to add a remote that points to the upstream repo.
git remote add upstream
  1. In your terminal, verify that the remotes have been set
git remote -v


We use yarn and yarn workspaces to develop the Carbon Gatsby theme. This allows us to have a development environment that’s closely linked to the theme with minimal setup. Run yarn install to install all of the projects dependencies.

This project has two packages: the actual theme package (gatsby-theme-carbon) and the example package. The example package emulates a project which uses the theme. Its only dependencies are Gatsby, React, and the adjacent theme package. The example package also serves as the theme’s documentation and website; it’s deployed on every merge to main.

New theme development will happen in the theme package while documentation and testing of that change will occur through changes in the example directory.

Development scripts

  • yarn dev – start the development environment
  • yarn dev:clean – clear cache and restart dev
  • yarn format – format your code with prettier
  • yarn lint - check for errors in your javascript
  • yarn test:prefix – build and serve with a path prefix

Work in a branch

You should always start a new project by pulling upstream changes into main and then creating a new branch. This workflow ensures you don’t accidentally commit anything to your main branch and get stuck when trying to open a pull request.

git checkout main
git pull upstream main
git checkout -b my-branch-name

Commit messages

For commit messages we use Angular commit conventions to dictate whether a commit is for a feature, fix, docs, etc. You need to prefix your commits with one of the following:

  • feat (feature)
  • fix (bug fix)
  • docs (documentation)
  • style (formatting, missing semi colons, …)
  • refactor
  • test (when adding missing tests)
  • chore (maintain)
git commit -m "chore: this is a test commit message"

Opening a Pull request

When you’re ready to open a pull request, push to your origin remote.

git push origin my-branch-name

You’ll get a message in your terminal with a URL to open up a pull request in the upstream repository. Navigate to that URL and be sure to give a detailed summary of your pull request in the title and body section of the form.

Sass and CSS Modules

For internal theme components we use Sass and CSS Modules. This allows us to take advantage of the Carbon Design System resources while not worrying about className collisions. By default, each .scss file will be supplied with all of the Carbon Sass variables: color, spacing, theme, and motion, as well as type and layout mixins, are imported automatically.

You should colocate your stylesheet with the component(s) that import it. If the component is TreeView then the stylesheet should be TreeView.module.scss. All contained within the TreeView directory.

CSS Modules

You don’t need to prefix your classes as CSS Modules will generate unique class names for you. Import the class from the .scss file.

.treeView {
color: $text-01;
import { treeView } from './style.css';
const TreeView = (props) => <div className={treeView} />;

For conditionally applying class names, use the classname library. Note how we’re using a computed property name for the property being based to cx. That’s because the className isn’t literally "long" it’s a value generated by CSS Modules and placed in the long variable.

import cx from 'classname';
import { treeView, long } from './style.css';
const TreeView = (props) => {
const className = cx(treeView, {
[long]: props.long,
const TreeView = (props) => <div className={className} />;

If you need to target a global class not processed by CSS Modules, you can do so with the global selector.

:global(.cds--grid) .codeBlock {
@include type-style('code-01');

VS Code

To get linting error feedback while writing javascript and SCSS in VS Code, install the stylelint and ESlint extensions. We use ESLint’s Prettier rules to format and lint all of our JavaScript in one pass. To get your code to format properly on save, add the following to a .vscode/settings.json in the root of your project

"editor.formatOnSave": true,
"[javascript]": {
"editor.formatOnSave": false
"[javascriptreact]": {
"editor.formatOnSave": false
"eslint.autoFixOnSave": true,

To lint the entire project and get errors in your Problems tray, you can add the following to a .vscode/tasks.json file in the root of your project. You can run these tasks with cmd+shift+d

"version": "2.0.0",
"tasks": [
"type": "npm",
"script": "lint:js",
"problemMatcher": "$eslint-stylish"

Test pages

If you want to add examples of what you are working on or see changes you’ve made, you can add an MDX file to packages/src/pages/test that will be visible at (your-server-name)/test/(added-file) during development. If you do add a page to the /test directory, update the below list with the file you added and its purpose to be included with your pull request.

  • Spacing audit: use this page to test spacing around components when combined in common patterns.


  1. Pull the latest from the main branch, usually by running git pull upstream main on your local machine.
  2. From the root of the package run yarn release.
  3. Follow the prompts accordingly.
  4. In the project’s release tab, edit the new release to include a summary of new changes.
Page last updated: 27 January 2020