stylish-commit

stylish-commit is a command-line tool and git pre-commit hook that checks your changes using simple lint scripts written in javascript.

Use it for simple tasks like:

• converting tabs to spaces
• removing trailing whitespace
• detecting usage of debugger and console.log

Operation

When you commit some code, the style scripts will be run against all staged changes. If a script has modified lines you will be prompted to change them, like:

Here, you have the option to:

• continue (ignores suggestions) - proceeds with the commit without making any changes.
• apply the suggestions - updates files with the suggested changes. This option takes you to another menu with the options to apply suggestions and commit, apply suggestions and cancel commit, ignore suggestions and cancel, or cancel (abort) the commit. This option will only be available if the changes can be applied cleanly (i.e. there are no unstaged changes to the file).
• select suggestions to apply - lets you pick which suggestions are applied when you select the option above.
• cancel (abort) the commit - so you can manually make changes.

Installation

For node/iojs projects, The hook can be installed automatically by running npm install stylish-commit-auto-hook-install --save-dev in your project's root folder. This will add stylish-commit-auto-hook-install to your project's dev-dependencies and automatically install the hook whenever someone installs dependencies with npm install.

You can also install the hook manually by running npm install stylish-commit -g then stylish-commit --install-hook. If you take this route, you'll need to manually install the hook for each clone of the project.

Creating style scripts

Style scripts sit in your project's .style directory1, and look like:

module.exports = {
  name: 'no-trailing-spaces',
  appliesTo: '**/*.+(js|txt)',
  validate: function (lines) {
    return lines.map(function (line) { return line.replace(/\s+$/, ''); });
  }
};

Each style script must have a name field and a validate function. It can also provide an appliesTo minimatch glob that restricts which modified files it checks.

The validate function receives an array of strings, each representing a changed line and is expected to return an array of the same length with either the unaltered line or a line containing modifications. e.g. the above script takes ['twas brillig and', 'the slithy    ', 'toves'] and returns ['twas brillig and', 'the slithy', 'toves']`.

There are some scripts to get you started at https://github.com/electronifie/style-guide.

Testing style scripts

You can test your scripts with the contents of a test file:

1. create a test file e.g. ~/foo.txt
2. ensure stylish-commit is globally installed with npm install -g stylish-commit
3. run stylish-commit -t ~/foo.txt from within the repo configured to use your style scripts

Alternative script formats

Regex search + replace

Runs a regex replace on each line. The with property can use dollar-notation (e.g. $1) to reference matching groups. The example below is functionally equivalent to the one above, just a bit easier to read.

module.exports = {
  name: 'no-trailing-spaces',
  appliesTo: '**/*.+(js|txt)',
  validate: { replace: /\s+$/, with: '' }
};

Known issues

• only works when committing from a terminal. The scripts will not run when committing from non-tty interfaces like IDEs or git GUIs.
• does not smartly handle multiple changes to the same line of the same file. In this case, only the last script to run's changes will be applied.