test-repo/docs/precommit.md

---
id: precommit
title: Pre-commit Hook
---

You can use Prettier with a pre-commit tool. This can re-format your files that are marked as "staged" via `git add` before you commit.

## Option 1. [lint-staged](https://github.com/okonet/lint-staged)

Install it along with [husky](https://github.com/typicode/husky):

```bash
yarn add lint-staged husky --dev
```

and add this config to your `package.json`:

```json
{
  "scripts": {
    "precommit": "lint-staged"
  },
  "lint-staged": {
    "*.{js,json,css,md}": ["prettier --write", "git add"]
  }
}
```

There is a limitation where if you stage specific lines this approach will stage the whole file after regardless. See this [issue](https://github.com/okonet/lint-staged/issues/62) for more info.

See https://github.com/okonet/lint-staged#configuration for more details about how you can configure lint-staged.

## Option 2. [pre-commit](https://github.com/pre-commit/pre-commit)

Copy the following config into your `.pre-commit-config.yaml` file:

```yaml
    -   repo: https://github.com/prettier/prettier
        sha: ''  # Use the sha or tag you want to point at
        hooks:
        -   id: prettier
```

Find more info from [here](http://pre-commit.com).

## Option 3. bash script

Alternately you can save this script as `.git/hooks/pre-commit` and give it execute permission:

```bash
#!/bin/sh
jsfiles=$(git diff --cached --name-only --diff-filter=ACM "*.js" "*.jsx" | tr '\n' ' ')
[ -z "$jsfiles" ] && exit 0

# Prettify all staged .js files
echo "$jsfiles" | xargs ./node_modules/.bin/prettier --write

# Add back the modified/prettified files to staging
echo "$jsfiles" | xargs git add

exit 0
```