React App Scaffolder

"Make the right thing the easy thing. A project's defaults become its culture." -- Adapted from engineering practice

"Strict from day one is cheaper than strict retrofitted." -- Adapted from TypeScript adoption experience

Core Philosophy

The first commit sets the project's defaults, and defaults are sticky: a project that starts without strict TypeScript, without a test runner, or without lint rarely gains them later without pain. This skill stands up the skeleton with the non-negotiables already on — strict types, Vitest, ESLint with the hooks and a11y plugins, a router, an error boundary, and a feature-folder layout — so the first real feature drops into a structured, tested, type-safe project.

Vite is the default bundler (fast, modern, ESM-native). Create React App is deprecated and is never the target for a new project — if an existing CRA app is in play, route to react-modernization-analyzer.

Grounding note: the KB has no React corpus. Use collection="javascript" for TS/tooling and cite react.dev / Vite + Vitest docs as the authority. Never invent a react collection.

Non-Negotiable Constraints:

1. Vite + TypeScript strict — strict: true in tsconfig from the first commit
2. Test runner wired — Vitest + React Testing Library with a test script and a passing smoke test
3. Lint + format wired — ESLint (react-hooks + jsx-a11y) and Prettier with scripts
4. Router from the start — a router with a typed route table and a not-found route
5. Error boundary at the shell — a top-level error boundary so one throw does not blank the app
6. Env via Vite convention — only VITE_* exposed to the client; secrets stay server-side
7. React Compiler wired — stable since React Compiler 1.0 (Oct 2025); by 2026 it is the default assumption for a new React project, not an opt-in experiment

What this skill is NOT:

• It is NOT a feature generator — use react-feature-slice / react-component-scaffolder for that
• It is NOT a deployment/CI guide — it covers the application skeleton; CI is a follow-up
• It is NOT a styling-framework decision — leave styling choice to the team

The 10 domain principles, knowledge-base lookups, discipline rules, the anti-pattern catalog, and error-recovery procedures live in references/conventions.md.

Workflow

Phase 1: DETECT

node -v && npm -v
ls package.json 2>/dev/null && echo "existing project — confirm before overwriting"
# If a Create React App project exists, STOP and route to react-modernization-analyzer.
grep -l "react-scripts" package.json 2>/dev/null && echo "CRA detected → modernization, not fresh scaffold"

If package.json already exists, do not clobber it — scaffold missing pieces only, and confirm first.

Phase 2: CREATE

npm create vite@latest <app-name> -- --template react-ts
cd <app-name>
npm install
npm install -D vitest @testing-library/react @testing-library/user-event jsdom \
  eslint-plugin-react-hooks eslint-plugin-jsx-a11y prettier babel-plugin-react-compiler
npm install react-router-dom

Phase 3: CONFIGURE

Apply the structure and config. See references/project-structure.md for full file contents.

src/
  app/
    App.tsx            # shell: providers + router + error boundary
    routes.tsx         # typed route table (home, layout, 404)
    ErrorBoundary.tsx  # top-level error boundary
  features/            # feature slices land here (react-feature-slice)
  shared/              # cross-cutting UI + utilities (http client, etc.)
  test/setup.ts        # RTL + jest-dom setup
  main.tsx             # createRoot
  vite-env.d.ts        # typed VITE_* env
eslint.config.js
vitest.config.ts
.env.example
.prettierrc
tsconfig.json          # strict

See references/toolchain-config.md for tsconfig, eslint.config.js (incl. compiler lint rules), vite.config.ts (React Compiler babel plugin), vitest.config.ts, and scripts.

Phase 4: VERIFY

npm run typecheck      # tsc --noEmit, strict
npm run lint           # eslint clean
npm run test           # smoke test green
npm run build          # production build succeeds
npm run dev            # dev server boots

State Block

<react-app-scaffold-state>
  phase: DETECT | CREATE | CONFIGURE | VERIFY | COMPLETE
  app_name: [name]
  existing_project: true | false
  cra_detected: true | false
  strict_ts: true | false
  router_configured: true | false
  test_harness_configured: true | false
  lint_configured: true | false
  error_boundary_added: true | false
  compiler_enabled: true | false
  last_action: [description]
  next_action: [description]
</react-app-scaffold-state>

Output Template

Emit the scaffold checklist (Toolchain · App Shell · Scripts · Verification) as the progress report. Full markdown checklist: references/conventions.md → "Scaffold Checklist (Output Template)".

Integration with Other Skills