| name | setup-pre-commit |
| disable-model-invocation | true |
| description | One-shot bootstrap of a Husky pre-commit gate for a JavaScript/TypeScript repo: lint-staged + Prettier on staged files, plus a full-project typecheck and test run on every commit. Scoped to JS/TS package.json repos only; leave Rust (cargo) and Python repos alone. An edit-time format/lint hook (if your harness runs one) already owns format/lint on individual writes; this skill's value-add is the whole-project typecheck + test gate that a per-file hook cannot provide. Manual: invoke /setup-pre-commit inside a JS/TS repo that has package.json and lacks a working pre-commit gate, when the user wants commit-time typecheck/test enforcement on top of edit-time linting. |
Setup Pre-Commit Hooks (JS/TS)
Bootstrap a commit-time gate for one JavaScript/TypeScript repository in a single pass.
Goal: Install a working Husky pre-commit gate in the current JS/TS repo — lint-staged + Prettier
on staged files, then a full-project typecheck and test run.
Success means:
- The repo has package.json and a detected package manager (npm/pnpm/yarn/bun)
- .husky/pre-commit contains and runs lint-staged, then typecheck, then test
- .lintstagedrc, a Prettier config, and the `prepare: "husky"` script all exist
- the hook body is verified for all three stages before `./.husky/pre-commit` or the exact hook commands run clean as the smoke test
Stop when: the gate is installed, the hook includes and passes lint-staged, typecheck, and test, and the original goal includes both typecheck and test.
Scope: JS/TS only
Run this only inside a JavaScript or TypeScript repo that carries a package.json. The whole apparatus (Husky, lint-staged, Prettier) is npm-ecosystem tooling; it has no business in a Rust crate, a Python project, or any non-Node tree.
Guard before doing anything:
- Confirm
package.json exists at the repo root. When it is absent, stop and tell the user this skill is JS/TS-only.
- Run
ls Cargo.toml pyproject.toml setup.py 2>/dev/null. When the repo is primarily Rust or Python (those files present, no meaningful package.json), stop and say so; a Rust/Python repo gets its own pre-commit story, not this one.
What this adds over the edit-time hook
An edit-time format/lint hook (PostToolUse on Edit/Write, if your harness runs one) already auto-fixes lint and format on each file as it is written, and a sound code-quality discipline treats that hook surface as owned. Re-running Prettier at commit time is belt-and-suspenders for human-authored or externally-pasted edits the hook never saw; the real value-add here is the part a per-file hook cannot give you: a full-project typecheck and test run gated on every commit. Keep that framing in mind; the typecheck + test lines are the point, lint-staged is the cheap fast pass that precedes them.
Steps
1. Detect the package manager
Check for a lockfile and pick the matching manager: package-lock.json → npm, pnpm-lock.yaml → pnpm, yarn.lock → yarn, bun.lockb → bun. Default to npm when none is present. Substitute the detected manager into every command and into the hook body below.
2. Install dev dependencies
Install husky lint-staged prettier as devDependencies with the detected manager (npm install -D ..., pnpm add -D ..., yarn add -D ..., bun add -d ...).
3. Initialize Husky
npx husky init
This creates .husky/ and adds prepare: "husky" to package.json. Husky v9+ needs no shebang in hook files.
4. Write .husky/pre-commit
Write the three-stage gate, fast pass first:
npx lint-staged
npm run typecheck
npm run test
Adapt the runner to the detected package manager. Read package.json scripts first. Treat any missing typecheck or test script as a blocking gap under this skill's original goal: add repo-appropriate scripts with the user, or confirm the user wants a downgraded lint-staged-only goal. Report the original goal successful only after both scripts exist and both hook commands run. Call a downgraded result lint-staged-only so it is distinct from the full typecheck/test gate.
5. Write .lintstagedrc
{
"*": "prettier --ignore-unknown --write"
}
--ignore-unknown skips files Prettier cannot parse (images and the like).
6. Write a Prettier config only when none exists
Create .prettierrc only when the repo has no Prettier config already (.prettierrc, .prettierrc.json, prettier.config.js, or a prettier key in package.json). Respect an existing config; overwriting it churns the repo and fights whatever convention is in place. Defaults when creating fresh:
{
"useTabs": false,
"tabWidth": 2,
"printWidth": 80,
"singleQuote": false,
"trailingComma": "es5",
"semi": true,
"arrowParens": "always"
}
7. Verify
Check each invariant:
.husky/pre-commit exists and is executable.lintstagedrc exists- the
prepare script in package.json reads "husky"
- a Prettier config exists
typecheck and test scripts exist in package.json for the original goal.husky/pre-commit contains the three stage commands in order: lint-staged, typecheck, test- Report any hook missing typecheck or test as a blocking gap, even when direct hook execution exits 0
- after the stage-order check passes, run
./.husky/pre-commit from the repo root; when direct hook execution is unavailable, run the exact command lines from .husky/pre-commit in order and require each to pass
8. Commit (ask first)
Ask the user before committing rather than auto-committing. When they say go, stage the created and changed files and commit with a subject like Add pre-commit hooks (husky + lint-staged + prettier), or hand the staged changes to /commit. The commit itself routes through the new gate, which doubles as the end-to-end smoke test that lint-staged, typecheck, and test all pass.
Notes
- Husky v9+ hook files need no shebang.
prettier --ignore-unknown keeps the staged pass from choking on binary or unparseable files.- The hook order is intentional: lint-staged is fast and staged-only, so it runs first; the full typecheck and test run after, since they are the slower, higher-value gate.
- When the repo already has a Husky setup or a different pre-commit framework (lefthook, simple-git-hooks, pre-commit), surface that to the user and ask before layering Husky on top; do not stack two gates blindly.
