Frontend Style Guidelines

This is a list of statements that describe how we do frontend development in Superset. While they might not be 100% true for all files in the repo, they represent the gold standard we strive towards for frontend quality and style.

• We develop using TypeScript.
• We use React for building components, and Redux to manage app/global state.
  • See: Component Style Guidelines and Best Practices
• We prefer functional components to class components and use hooks for local component state.
• We use Ant Design components from our component library whenever possible, only building our own custom components when it's required.
• We use @emotion to provide styling for our components, co-locating styling within component files.
  • See: Emotion Styling Guidelines and Best Practices
• We use Jest for unit tests, React Testing Library for component tests, and Cypress for end-to-end tests.
  • See: Testing Guidelines and Best Practices
• We add tests for every new component or file added to the frontend.
• We organize our repo so similar files live near each other, and tests are co-located with the files they test.
• We prefer small, easily testable files and components.
• We use ESLint and Prettier to automatically fix lint errors and format the code.
  • We do not debate code formatting style in PRs, instead relying on automated tooling to enforce it.
  • If there’s not a linting rule, we don’t have a rule!
• We use React Storybook and Applitools to help preview/test and stabilize our components
  • Note: a public instance Storybook reflecting the master branch is available here.

References

[SIP-36] Proposal for standardizing use of TypeScript

This SIP formally adopted TypeScript as the main language for Superset frontend, started migration work for JavaScript => TypeScript, and added the requirement that all new frontend JavaScript should be written in TypeScript instead.

[SIP-37] Proposal to implement CSS-in-JS using Emotion

This SIP formally adopted Emotion as the method for adding styling to components, describes alternatives considered, and why migration is valuable.

[SIP-48] Using Ant Design as our primary component library

This SIP replaced Bootstrap with Ant Design as our main component library, and describes how they should interact with style overrides provided by Emotion.

[SIP-56] Adopt React Testing Library for testing React components

This SIP replaced Enzyme with React Testing Library for testing React components, primarily because RTL is the most used testing framework and fully supports the newest React features.

[SIP-61] Improve the organization of front-end folders

This SIP describes how we organize our frontend folders, including how we should group different types of modules and components, where tests should be located, and how files should be named.