uglify-save-license

License detector for UglifyJS

npm install uglify-save-license
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uglify-save-license

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License detector for UglifyJS

Overview

This module enables us to preserve license comments when using UglifyJS.

Even if the license statement is in multiple line comments, or the comment has no directive such as @license and /*!, this module keeps them readable.

Installation

Install via npm.

npm install uglify-save-license

Make sure you have installed Node before running this command.

Usage

First of all, load uglify-save-license module.

var saveLicense = require('uglify-save-license');

Use with UglifyJS

Pass this module to the comments option.

var result = UglifyJS.minify('file1.js', {
  output: {
    comments: saveLicense
  }
});

Use with grunt-contrib-uglify

Pass this module to the preserveComments option.

grunt.initConfig({
  uglify: {
    my_target: {
      options: {
        preserveComments: saveLicense
      },    
      src: ['src/app.js'],
      dest: 'dest/app.min.js' 
    }
  }
});

How it works

uglify-save-license checks each comment token of a JavaScript file. The comment will be regarded as a license statement and preserved after compression, if it meets at least one of the following requirements:

  1. The comment is in the first line of a file.
  2. The regexp for license statement matches the string of the comment. It matches, for example, MIT and Copyright.
  3. There is a comment at the previous line, and it matches 1. 2. or 3.

Examples

CLI tool example

Main script (uglify-example.js)

#!/usr/bin/env node

var UglifyJS    = require('uglify-js'),
    saveLicense = require('uglify-save-license');

var minified = UglifyJS.minify(process.argv[2], {
  output: {
    comments: saveLicense
  }
}).code;

console.log(minified);

Target file

// First line

// (c) 2014 John  <- contains '(c)'
// The previous line is preserved

// This line won't be preserved.
(function(win, doc) {
  var str = 'Hello World! :' + doc.title;

  // This line will not, too.
  console.log(str);
}(window, document));

Command

node uglify-example.js <target filename>

Output

// First line
// (c) 2014 John  <- contains '(c)'
// The previous line is preserved
!function(o,l){var n="Hello World! :"+l.title;console.log(n)}(window,document);

Gruntfile.coffee example

module.exports = (grunt) ->

  grunt.loadNpmTasks 'grunt-contrib-uglify'
  grunt.loadNpmTasks 'grunt-contrib-concat'
  grunt.loadNpmTasks 'grunt-contrib-clean'

  grunt.initConfig
    uglify:
      target:
        options:
          preserveComments: require 'uglify-save-license'
        files: [
          expand: true
          flatten: true
          cwd: 'path/to/src'
          src: ['**/*.js']
          dest: 'tmp/'
        ]

    concat:
      js:
        src: ['tmp/*.js']
        dest: 'path/to/build/app.js'

    clean:
      tmpdir: ['tmp']

  grunt.registerTask 'default' ['uglify', 'concat', 'clean']

Acknowledgements

uglify-save-license is inspired by grunt-license-saver and I used it as reference. Thanks, kyo-ago.

License

Copyright (c) 2013 - 2014 Shinnosuke Watanabe

Licensed under the MIT license.

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