Storybook for Firefox

Storybook is a component library to document our design system, reusable components, and any specific components you might want to test with dummy data. Take a look at our Storybook instance!


Storybook lists components that can be reused, and helps document what common elements we have. It can also list implementation specific components, but they should not be added to the “Design System” section.

Changes to files directly referenced from Storybook (so basically non-chrome:// paths) should automatically reflect changes in the opened browser. If you make a change to a chrome:// referenced file then you’ll need to do a hard refresh (Cmd+Shift+R/Ctrl+Shift+R) to notice the changes. If you’re on Windows you may need to ./mach build faster to have the chrome:// URL show the latest version.

Running Storybook

Installing the npm dependencies and running the storybook npm script should be enough to get Storybook running. This can be done via ./mach storybook commands, or with your personal npm/node that happens to be compatible.

Running with mach commands

This is the recommended approach for installing dependencies and running Storybook locally.

To install dependencies and start Storybook, just run:

# This uses npm ci under the hood to install the package-lock.json exactly.
./mach storybook

This single command will first install any missing dependencies then start the local Storybook server. You should run your local build to test in Storybook since chrome:// URLs are currently being pulled from the running browser, so any changes to common-shared.css for example will come from your build.

The Storybook server will continue running and will watch for component file changes. To access your local Storybook preview you can use the launch subcommand:

# In another terminal:
./mach storybook launch

This will run your local browser and point it at http://localhost:5703. The launch subcommand will also enable SVG context-properties so the fill CSS property works in storybook.

Alternatively, you can simply navigate to http://localhost:5703/ or run:

# In another terminal:
./mach run http://localhost:5703/

although with these options SVG context-properties won’t be enabled, so what’s displayed in Storybook may not exactly reflect how components will look when used in Firefox.

Personal npm

You can use your own npm to install and run Storybook. Compatibility is up to you to sort out.

cd browser/components/storybook
npm ci # Install the package-lock.json exactly so lockfileVersion won't change.
npm run storybook

Updating Storybook dependencies

On occasion you may need to update or add a npm dependency for Storybook. This can be done using the version of npm packaged with mach:

# Install a dev dependency from within the storybook directory.
cd browser/components/storybook && ../../../mach npm i -D your-package

Adding new stories

Storybook is currently configured to search for story files (any file with a .stories.(js|mjs) extension) in toolkit/content/widgets and browser/components/storybook/stories.

Stories in toolkit/content/widgets are used to document design system components. The easiest way to use Storybook for non-design system elements is to add a new .stories.mjs file to browser/components/storybook/stories.

If you want to colocate your story with the code it is documenting you will need to add to the stories array in the .storybook/main.js configuration file so that Storybook knows where to look for your files.

The Storybook docs site has a good overview of what’s involved in writing a new story. For convenience you can use the Lit library to define the template code for your story, but this is not a requirement.