grunt-diff

Run tasks only if target file changed.

Getting Started

This plugin requires Grunt ~0.4.0

If you haven't used Grunt before, be sure to check out the Getting Started guide, as it explains how to create a Gruntfile as well as install and use Grunt plugins. Once you're familiar with that process, you may install this plugin with this command:

npm install grunt-diff --save-dev

Once the plugin has been installed, it may be enabled inside your Gruntfile with this line of JavaScript:

grunt.loadNpmTasks('grunt-diff');

The "diff" task

Overview

This task will keep a hash reference of target file and run defined tasks only if file changed. Similar to grunt-contrib-watch, but this one is for deployment.

File hashes will be saved in .grunt/grunt-diff/hash.json. You might like to add .grunt to your .gitignore.

grunt.initConfig({
  diff : {
    javascript : {
      src   : [ 'lib/*.js' ],
      tasks : [ 'concat', 'uglify' ],
    },
    sass : {
      refer : 'sass:dist',
      tasks : 'sass:dist',
    },
  },
});

You can flush file hashes any time by running:

grunt diff:flush

Options

options.algorithm

Type: String Default value: 'md5'

algorithm is dependent on the available algorithms supported by the version of OpenSSL on the platform. Examples are 'sha1', 'md5', 'sha256', 'sha512', etc. On recent releases, openssl list-message-digest-algorithms will display the available digest algorithms.

options.encoding

Type: String Default value: 'utf8'

The file encoding.

Usage Examples

Notice that targets are passed to diff task in the same order they are written in Gruntfile. Thus allows chained configuration.

grunt.initConfig({
  // Other configs

  diff : {
    single : {
      src   : 'file/to/check',
      tasks : [ 'taskToRun' ],
    },

    pattern : {
      files : [{
        expand : true,
        cwd    : 'path/to/check',
        src    : [ '**/*' ],
      }],
      tasks : [ 'taskToRun' ],
    },

    chained : {
      src   : 'files/generated/by/previous/task',
      tasks : [ 'taskToRun' ],
    },

    multi : {
      src   : 'file/to/check',
      tasks : [
        'taskToRun1',
        'taskToRun2',
      ],
    },

    refer : {
      refer : 'task:target',
      tasks : [ 'taskToRun' ],
      // 'tasks' can be omited when using 'refer'.
      // Defaults to the refered 'task:target'.
    },
  },
});

TODO

• Improve test coverage

Contributing

In lieu of a formal styleguide, take care to maintain the existing coding style. Add unit tests for any new or changed functionality. Lint and test your code using Grunt.

Release History

• 2014-02-10 v0.1.5 Skip non-file paths
• 2014-02-10 v0.1.3 Default refer tasks
• 2014-02-10 v0.1.2 Refer to task:target's files
• 2014-02-10 v0.1.1 Check file removal
• 2014-02-10 v0.1.0 Release