Setup pre commit

Setup Pre-Commit

One-time team-shared setup of husky + lint-staged + prettier. Adapted from mattpocock's setup-pre-commit + hub's setup-hooks.

This is not part of the bootstrap script — bootstrap drops local-only files. Pre-commit is committed to the repo and runs for every teammate. Invoke this skill explicitly.

Workflow

1. Detect package manager

Check for the lockfile present in the repo root:

Lockfile	Manager
pnpm-lock.yaml	pnpm
yarn.lock	yarn
bun.lockb	bun
package-lock.json	npm

Default to npm if none present.

1a. Enforce pnpm-only (only if pnpm detected)

If the detected manager is pnpm, lock down the repo so teammates and CI can't accidentally use npm/yarn/bun. Skip this step entirely for other managers — don't migrate them silently.

Ask the user once: "Detected pnpm. Enforce pnpm-only (packageManager + preinstall: only-allow pnpm + .npmrc engine-strict)?" Default yes; honor --no-enforce-pm if supplied.

If yes:

1. packageManager field (corepack pickup):

   PNPM_VERSION=$(pnpm --version)
   npm pkg set packageManager="pnpm@${PNPM_VERSION}"
   

2. preinstall script — hard stop for npm/yarn/bun:

   npm pkg set scripts.preinstall='npx only-allow pnpm'
   

   only-allow is a tiny pinpm/pnpm helper invoked via npx. No new dep — runs only at install time.

3. .npmrc engine-strict — refuses install if the engines field doesn't match:

   touch .npmrc
   grep -qE '^engine-strict\s*=' .npmrc || echo 'engine-strict=true' >> .npmrc
   

4. Smoke-test: run npm install --dry-run in a scratch shell — should fail with only-allow message. Run pnpm install --frozen-lockfile — should pass.

Note: npm pkg set itself uses npm, but only to mutate package.json (no install). Safe under the local hook (block-non-pnpm.sh allows npm pkg).

2. Detect tooling already in package.json

Look for: eslint, biome, oxlint, prettier, and typecheck/test scripts. Only configure what's already installed (don't install new linters as a side effect).

3. Install dependencies

# pnpm example
pnpm add -D husky lint-staged

# add prettier ONLY if not present
pnpm add -D prettier

4. Initialize husky

npx husky init   # v9+, no shebang needed in hook files

This creates .husky/ and adds "prepare": "husky" to package.json.

5. Write .lintstagedrc (or lint-staged block in package.json)

Minimal version that adapts to detected tooling:

{
  "*.{js,jsx,ts,tsx}": ["eslint --fix", "prettier --write"],
  "*.{json,css,scss,md}": "prettier --write"
}

If only Prettier is configured:

{
  "*": "prettier --ignore-unknown --write"
}

6. Write .husky/pre-commit

npx lint-staged

Add npm run typecheck and npm run test lines ONLY if those scripts exist in package.json and the user wants the slower hook. Default: just lint-staged for speed.

7. Add prepare script (if not added by husky init)

npm pkg set scripts.prepare="husky || true"

The || true prevents CI failures where husky isn't needed.

8. Smoke test

Stage a small change (touch a file, then commit). The hook runs lint-staged. If it passes, the setup is good.

9. Commit

git add .husky/ package.json package-lock.json .lintstagedrc 2>/dev/null || true
git add .husky/ package.json pnpm-lock.yaml .lintstagedrc .npmrc 2>/dev/null || true
# (adapt to actual files changed)

git commit -m "chore: add husky + lint-staged pre-commit hook"

If the pnpm-only step (1a) ran, the commit also includes packageManager, scripts.preinstall, and .npmrc. Either roll into one commit with message chore: add pre-commit hooks + enforce pnpm-only or split into two — user's call.

NO Co-Authored-By trailer, NO "Generated with Claude Code" footer (per project conventions).

Notes

• prettier --ignore-unknown skips files Prettier can't parse (images, binaries)
• Husky v9+ doesn't need shebangs in hook files
• If you want to add typecheck/test to the pre-commit hook, warn the user — slower commits affect every teammate