#git-validate

This is a super simple framework to facilitate creating your own modules similar to precommit-hook.

Usage

This module isn't intended to be used directly in your projects (thought it can be), but rather as the dependency of a module that you create that will act as a template of sorts.

To create a validate module, first make a new directory and use npm init to initialize your module:

mkdir validate-nlf
cd validate-nlf
npm init

Follow the prompts, and when complete install this module:

npm install --save git-validate

Now, let's say we want to provide a default .jshintrc file, let's go ahead and create that file in our new directory and fill it with some options:

vim jshintrc

{
  "node": true,

  "curly": true,
  "latedef": true,
  "quotmark": true,
  "undef": true,
  "unused": true,
  "trailing": true
}

Note that we saved the file as jshintrc without the leading dot.

Next, let's create our install script:

vim install.js

var Validate = require('git-validate');

Validate.copy('jshintrc', '.jshintrc');

This instructs git-validate to copy the jshintrc file in our module to .jshintrc in the root of the project that installs it.

Now we edit our package.json to tell it about our install script:

  "scripts": {
    "install": "node install.js"
  }

And that's it for the simplest possible example. Now anytime you install validate-nlf you'll automatically get a .jshintrc file in your project.

This wouldn't be any fun without the git hooks though, so let's extend it a bit further to make sure that jshint is run any time a user tries to git commit after installing our module. To do so, let's create a validate.json file with the following contents:

{
  "scripts": {
    "lint": "jshint ."
  },
  "pre-commit": ["lint"]
}

And then let's add a line to our install.js to make sure it gets installed as .validate.json (note the leading dot).

Validate.copy('validate.json', '.validate.json', { overwrite: true });

Great, that's it! You'll notice the { overwrite: true } object as the last parameter to copy. This tells git-validate that it's ok to overwrite an existing file. Without that option, the copy method would fail silently if the file already exists. That's why we didn't use it for our .jshintrc because that's something a user should be able to configure.

Now when a user tries to run git commit git-validate will open .validate.json and see that the pre-commit event wants to run the lint script. It will load your project's package.json to see if you have a lint script defined there first. If you do not, it will use the lint script present in the .validate.json file and run it. If the script fails, the commit is denied. Easy!

The Details

Copy

git-validate exports a copy method. This is the only exported method you should ever need. It has the signature:

Validate.copy(source, target, options);

Where source is a path relative to your install script, and target is a path relative to the root of the project that is installing the module. For example if my module has the layout:

bin/install
jshintrc

And I wish for the file jshintrc to be placed in the root of projects as .jshintrc, I would call Validate.copy('../jshintrc', '.jshintrc').

Note that source may be a file or a directory. If a directory is specified than a new directory will be created at target and the full contents of source will be copied to the target directory recursively.

The only option currently available is overwrite. When set to true overwrite will always copy the given file, overwriting any existing destination file. If this is not set, copy will instead silently fail and leave the old file in place. I highly recommend always using { overwrite: true } on your .validate.json file.

.validate.json

This is the file that configures the git hooks. It currently supports two keys, scripts and pre-commit.

The scripts property should be an object with named scripts, exactly the same as the scripts property in your package.json. This gives you a place to define some default scripts to be used in your hooks. Note that any script defined in your package.json will take precedence over one defined in .validate.json. This is what makes it safe to always overwrite .validate.json with the newest possible copy, since if your project requires changes to the scripts, you can make them in package.json instead.

The pre-commit key must be an array of script names to be run. If any of the scripts are not defined, they will be skipped and a message will be printed showing that no script was found, as such it is safe to set scripts here that you wish to always be custom in every project. The .validate.json file for precommit-hook looks like this:

{
  "scripts": {
    "lint": "jshint ."
  },
  "pre-commit": ["lint", "validate", "test"]
}