/setup-pre-commit

name: setup-pre-commit
description: Set up Husky pre-commit hooks with lint-staged (Prettier), type checking, and tests in the current repo. Use when user wants to add pre-commit hooks, set up Husky, configure lint-staged, or add commit-time formatting/typechecking/testing.

Setup Pre-Commit Hooks

What This Sets Up

• **Husky** pre-commit hook
• **lint-staged** running Prettier on all staged files
• **Prettier** config (if missing)
• **typecheck** and **test** scripts in the pre-commit hook

Steps

1. Detect package manager

Check for `package-lock.json` (npm), `pnpm-lock.yaml` (pnpm), `yarn.lock` (yarn), `bun.lockb` (bun). Use whichever is present. Default to npm if unclear.

2. Install dependencies

Install as devDependencies:

husky lint-staged prettier

3. Initialize Husky

npx husky init

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

4. Create `.husky/pre-commit`

Write this file (no shebang needed for Husky v9+):

npx lint-staged
npm run typecheck
npm run test

**Adapt**: Replace `npm` with detected package manager. If repo has no `typecheck` or `test` script in package.json, omit those lines and tell the user.

5. Create `.lintstagedrc`

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

6. Create `.prettierrc` (if missing)

Only create if no Prettier config exists. Use these defaults:

{
  "useTabs": false,
  "tabWidth": 2,
  "printWidth": 80,
  "singleQuote": false,
  "trailingComma": "es5",
  "semi": true,
  "arrowParens": "always"
}

7. Verify

• [ ] `.husky/pre-commit` exists and is executable
• [ ] `.lintstagedrc` exists
• [ ] `prepare` script in package.json is `"husky"`
• [ ] `prettier` config exists
• [ ] Run `npx lint-staged` to verify it works

8. Commit

Stage all changed/created files and commit with message: `Add pre-commit hooks (husky + lint-staged + prettier)`

This will run through the new pre-commit hooks: a good smoke test that everything works.

Notes

• Husky v9+ doesn't need shebangs in hook files
• `prettier --ignore-unknown` skips files Prettier can't parse (images, etc.)
• The pre-commit runs lint-staged first (fast, staged-only), then full typecheck and tests