uglify-save-license


A support module for UglifyJS to detect and preserve license comments

``javascript
// Backbone.js 1.1.2

// (c) 2010-2014 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
// Backbone may be freely distributed under the MIT license.
// For all details and documentation:
// http://backbonejs.org

(function(root, factory) {

// Set up Backbone appropriately for the environment. Start with AMD.
if (typeof define === 'function' && define.amd) {
define(['underscore', 'jquery', 'exports'], function(_, $, exports) {
//...
`

↓

`javascript
// Backbone.js 1.1.2
// (c) 2010-2014 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
// Backbone may be freely distributed under the MIT license.
// For all details and documentation:
// http://backbonejs.org
!function(a,b){if("function"==typeof define&&define.amd)define(["underscore","jquery","exports"],function(c,d,e){a.Backbone=b(a,e,c,d)});else if("undefined"!=typeof exports){...
`

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 with npm. (Make sure you have installed Node.)

`
npm install --save-dev uglify-save-license
`

Usage

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

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

$3

Pass this module to the comments option.

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

$3

Pass this module to the preserveComments option.

`javascript
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

$3

#### Main script (uglify-example.js)

`javascript
#!/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

`javascript
// 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
`

#### Output

`javascript
// 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);
`

$3

`coffeescript
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.