Building a React Component Library from Scratch

Building a shared component library saves time across projects and teams. But doing it well requires attention to build configuration, documentation, testing, and publishing. Here is the complete process.

Project Structure

Organize components in a flat structure: src/components/Button, src/components/Input, etc. Each component directory contains the component file, types, tests, stories, and an index.ts barrel export. The root src/index.ts exports everything. This structure makes it easy to find, test, and document each component independently.

TypeScript and Build Configuration

Use tsup for building — it handles TypeScript compilation, tree-shaking, and dual CJS/ESM output. Configure it to generate .d.ts type declarations alongside the JavaScript output. Set sideEffects: false in package.json so bundlers can tree-shake unused components. Export each component individually via the exports field for optimal import granularity.

Styling Strategy

For maximum flexibility, use CSS Modules or Tailwind CSS (with the tw-merge pattern for variant handling). Avoid CSS-in-JS libraries that require runtime — they add bundle size and create framework lock-in. If you use Tailwind, ship the component source with Tailwind classes and let consumers compile them with their own Tailwind configuration.

Storybook Documentation

Every component needs a Storybook story showing its variants, states, and interactions. Use autodocs to generate documentation from TypeScript props and JSDoc comments. Add play functions for interaction testing — click a button, fill a form, verify the output. Storybook doubles as your component playground and visual regression test suite.

Publishing and Versioning

Publish to npm with semantic versioning. Use changesets for managing version bumps and generating changelogs across a monorepo. Set up a GitHub Action that creates a release PR when changesets are merged, and publishes to npm when the release PR is merged. This gives you automated, predictable releases with human review at the version bump stage.