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Bulb Design

Welcome to the Bulb Design repository ūüĎč

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Table of contents

Viewing the design system documentation

The latest version of the design system documentation is published at http://design.bulb.co.uk where you can browse the library and try new pattern arrangements in the playgrounds.

Consuming the design library

To use the patterns in your project, first, add the @bulb/design package.

Note: this is a private package, and you will need to login to npm and be added to the Bulb npm organisation.

yarn add @bulb/design

You can then simply import the components you wish to use, if you're using the full project.

Working with components

import { Dropdown } from '@bulb/design/modules/Dropdown';
<Dropdown {...props} />;

Local Development


This repository is split into multiple yarn workspaces:

  • @bulb/design (./packages/design) - component library for the design system.
  • e2e (./e2e) - end to end tests for the various components in this repo, mainly vr-tests for the component library.
  • website (./website) - documentation website for the design system.

Working with yarn workspaces is very similar to normal packages. Just prefix the yarn command with workspace <workspacename> (where <workspacename> is the name key in the package.json of the workspace).

For example, to run yarn test in the component library package, you should type:

yarn workspace @bulb/design test

To install dependencies, just run yarn install in any workspace folder (preferably the repo root).

See the yarn workspaces documentation for more information.

Viewing the design system documentation locally

To run the documentation website locally run the following command.

yarn workspace website start

This will run it in a hot mode and will update any browser windows (on modern browsers) with any changes you make locally.

Creating Patterns

See the Solar technical styleguide for details about how to structure and write new patterns.

Tracking changes

We use changelogs for patterns to help document the changes to components over time.

This helps us when consuming components that have been changed by one another to see why and how components have changed.

When updating components, we update the adjacent CHANGELOG.md file with an entry describing the change where appropriate.

New changes should be added under the vNext section at the top of the changelog file.

  • For breaking component changes prefix the entry with [major] to communicate the new behaviour.
  • For new feature prefix the entry with [minor] to communicate the new behaviour.
  • For bug fixes prefix the entry with [patch] to communicate the new behaviour.

example changelog structure

## vNext
- [major] short description of breaking change
- [minor] short description of new feature
- [patch] short description of bug fix
- short description of non breaking change
## v17.0.1
// ...previous changes

Pattern Documentation

We utilise docz to create a visual reference to all the patterns we've built in here and mdx to write both JSX and component documentation.

When you add a new pattern to this repo, the README.mdx should be filled with details of this pattern.

It is generally the same Markdown as with Github, with the addition of Specimens - read about those over here to make your documentation amazing.

If you need to do any styling or functional changes to specimens - docz theme solar is a separate repository

Static Variables and Values

Static values and CSS variables are in the src/styles directory.

In your components, you can import these,

import { palette } from '../../styles/palette';

Using global styles

At Bulb we use styled-components to enable styles to be developed at a component level.

However, not everything should be a component style in the first place, things like font-families, line-heights, and focus styles are better placed as global (base) styles because:

  1. We want to use them everywhere
  2. Aside from a few exceptions, we want to use them everywhere the same way
  3. They should be low specificity, and easy to override where needed anyway

With focus styles, it’s particularly helpful because

  1. In almost all cases, we want to use the same focus style
  2. Focus styles are mandatory for WCAG AA accessibility, so we don’t have to think about whether one is needed or not
  3. It’s difficult to test for focus styling, and few automated accessibility testing tools report them where they are missing

We commit to having focus styles written for each component but it is not systemically robust and dependable to rely on the development process to ensure these are always present and well setup.


import { createGlobalStyle } from 'styled-components';
import { global } from '@bulb/design/styles/Global';
// with default responsive behaviour
const GlobalStyle = createGlobalStyle`
// with custom responsive behaviour
const GlobalStyle = createGlobalStyle`
    responsiveBehaviours: [
      { fontSize: '16px' },
      { minWidth: '731px', fontSize: '20px' },
      { minWidth: '1695px', fontSize: '26px' },

Default viewports

span: 3
  - Responsive Step: initial
    Font Size: 16px
  - Responsive Step: 667px
    Font Size: 20px
  - Responsive Step: 1695px
    Font Size: 26px

Two Column viewports

Used with two column layouts ie. magenta (bulb account)

span: 3
  - Responsive Step: initial
    Font Size: 16px
  - Responsive Step: 1024px
    Font Size: 20px
  - Responsive Step: 1695px
    Font Size: 26px


Unit tests and snapshots

run unit tests on the design library

The test command is

yarn workspace @bulb/design test

You can add any of the Jest CLI options to test specific files.

Your tests should cover any interactions your component may have.

update non vr snapshots

The command is

yarn workspace @bulb/design test -u

Visual regression tests

We use visual regression tests to give us confidence in our component's visual behaviour when making changes.

Visual regression tests should be setup for component's in adjacent {ComponentName}.vr-test.tsx files, and generate snapshots into an adjacent image_snapshots folder.

Running visual regression tests locally

docker setup

This command only needs to be run once per development machine. Docker will save browserless/chrome locally for you to use any time in the future.

docker pull browserless/chrome:release-puppeteer-1.10.0

run the docker machine

In order to run the visual regression tests in development, you will need to be running the browserless/chrome:release-puppeteer-1.10.0 docker image locally running on port 8080.

To do so run the following command prior to running the visual regression tests. You can leave it running in the background for future test runs, or terminate and rerun before running tests again.

yarn workspace e2e run docker-vr

run the vr tests

The test command is

yarn workspace e2e vr-test

If there are any changes to the snapshots, a diff file is generated next to the existing snapshots.

Updating vr snapshots

Once you have confirmed that the snapshot diffs are expected, you can update the snapshots by running:

yarn workspace e2e vr-test -u

Example Usage

- /ElementName
  - /**image_snapshots**
    - elementname-vr-test-tsx-execution-one-large-1.snap.png
    - elementname-vr-test-tsx-execution-one-small-1.snap.png
    - elementname-vr-test-tsx-execution-two-large-1.snap.png
    - elementname-vr-test-tsx-execution-two-small-1.snap.png
  - index.tsx
  - styled.tsx
  - ElementName.test.tsx
  - ElementName.vr-test.tsx
// ElementName.vr-test.tsx
import { snapshotComponent, largeViewport, smallViewport } from 'e2e/vr-test';
const screenshotOptions = {
  // by default we use the bounding box of the components container
  // this allows you to test for components that break out of this
  clip: {
    width: 250,
    height: 100,
    x: 0,
    y: 0,
describe('execution-one', () => {
  const componentExecutionOne = <Component execution="one" />
  it('large', async () => {
    const snapshot = await snapshotComponent(componentExecutionOne, {
      viewport: 'large',
  it('narrow', async () => {
    const snapshot = await snapshotComponent(componentExecutionOne, {
      viewport: 'narrow',
describe('execution-two', () => {
  const componentExecutionTwo = <Component execution="two" />
  it('large', async () => {
    const snapshot = await snapshotComponent(componentExecutionTwo, {
      viewport: 'large',
  it('narrow', async () => {
    const snapshot = await snapshotComponent(componentExecutionTwo, {
      viewport: 'narrow',

Troubleshooting guide

Use the troubleshooting guide for resolving any errors when updating the design library




npm i @bulb/patterns

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