# How to lint your commit messages

You just learned about [Conventional Commits](https://www.conventionalcommits.org/en/v1.0.0/) specification and its benefits, and would like to adopt it. Change is difficult, how do you make sure you never go rogue again? The answer to that is simple, using [commitlint](https://commitlint.js.org/#/) to lint your commit messages.

## What is commitlint?

[Commitlint](https://commitlint.js.org/#/) is a tool that lints your commit messages and helps your team adhere to a commit convention. By supporting npm-installed configurations it makes sharing of commit conventions easy.

## Setup commitlint

To get started, create an empty project:

```bash
# Create a new directory
mkdir using-commitlint
# Open the directory
cd using-commitlint
# Create a git repository
git init
# Create a package.json (use default configuration)
npm init
```

Now install as a dev dependency commitlint and a config for it, in our case it is config-conventional.

```bash
npm install --save-dev @commitlint/cli @commitlint/config-conventional
```

To configure commitlint to use conventional commits config, create a file named `commitlint.config.js` and inside it add:

```javascript
module.exports = {
    extends: ["@commitlint/config-conventional"]
};
```

To run commitlint before the code is committed and block the commit in case of lint errors we'll need to use git hooks, to make that easy we'll install [husky](https://typicode.github.io/husky/), a git hooks helper:

```bash
# Install husky
npm install --save-dev husky
# Activate hooks
npx husky install
```

The last step is to register a hook:

```bash
npx husky add .husky/commit-msg  'npx --no -- commitlint --edit ${1}'
```

To test try to create a commit with a message that violates the conventional commits specification:

```bash
git commit -m "this message is in clear violation of the specification" #fail
#⧗   input: this message is in clear violation of the specification
#✖   subject may not be empty [subject-empty]
#✖   type may not be empty [type-empty]
#
#✖   found 2 problems, 0 warnings
#ⓘ   Get help: https://github.com/conventional-changelog/commitlint/#what-is-commitlint
#
#husky - commit-msg hook exited with code 1 (error)
```

And if you try a valid message it should pass:

```bash
git commit -m "feat(my-scope): the description goes right here" #success
```

## Additional resources

[\[commitlint CI setup\]](https://commitlint.js.org/#/guides-ci-setup) - Here we configured a local setup of commitlint, to enforce commit conventions with confidence you should lint on your CI server.

[\[commitlint prompt\]](https://commitlint.js.org/#/guides-use-prompt) - If your are having a tough time to remember the structure of the convention that you chose, use a prompt to help with authoring a commit.

[\[Conventional commits specification\]](https://www.conventionalcommits.org/en/v1.0.0/) - Learn more about conventional commits specification.

[\[commitlint configs\]](https://github.com/conventional-changelog/commitlint/tree/master/%40commitlint) - Explore other commitlint configurations available on npm