grunt-minify-polymer

Grunt plugin for minifying Polymer Elements. This plugin has been created to combine functionalities of grunt-minify-html, gulp-minify-inline and vulcanize#0.7.11 for Polymer v1.0 Elements.

This plugin is made to solve two issues:

1. Resolving issues with ':root' and '@apply' CSS rules found in Polymer.

   In css-clean:

   • ':root' minifies incorrectly, missing a closing brace.
   • '@apply' compiles incorrectly, either being ignored or being prepended with an invalid ':'.

   In general, CSS Parsers currently fail on these rules, producing errors whilst attempting to minify. Thus this plugin uses simple regex with the aim of simply removing comments and whitespace present in the CSS.

2. Minifying inline CSS and JS in element HTML.

   Polymer Elements contain their documentation inline the element HTML, JS and CSS. Vulcanize may not fully remove the documentation comments, and will not minify automatically. This plugin aims to bridge the step from source code to vulcanized production code by producing an intermediary step with minified source code for vulcanize.

Getting Started

This plugin requires Grunt.

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-minify-polymer --save-dev

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

grunt.loadNpmTasks('grunt-minify-polymer');

ES6 Support

If you require support for minifying ES6, please target the ES6 build by installing as above, and appending -es6 to the version in your package.json.

...
"dependencies": {
  "grunt-minify-polymer": "vx.x.x-es6"
},
...

The "minifyPolymer" task

Minifies HTML with any inline CSS and JS.

Overview

In your project's Gruntfile, add a section named minifyPolymer to the data object passed into grunt.initConfig().

grunt.initConfig({
  minifyPolymer: {
    options: {
      // Task-specific options go here.
    },
    your_target: {
      // Target-specific file lists and/or options go here.
    }
  }
})

Options

See minimize options for options to pass for HTML Minification.

options.jsCompress

Type: Object Default Value : { warnings: false }

Object passed to UglifyJS when compressing inline JS.

options.jsMangle

Type: Boolean Default value: true

Allow UglifyJS to mangle function and local variable names.

Usage Examples

Static File Bindings

grunt.initConfig({
  minifyPolymer: {
    default: {
      files: {
        'dest/my-element.html': 'src/my-element.html',
        'dest/my-other-element.html': 'src/my-other-element.html'
      }
    }
  }
});

Dynamic File Bindings

grunt.initConfig({
  minifyPolymer: {
    default: {
      files: [
        {
          expand: true,
          cwd: 'src/html/',
          src: ['**/*.html'],
          dest: 'build/'
        }
      ]
    }
  }
});

Minify Polymer-Elements from Bower

grunt.initConfig({
  minifyPolymer: {
    default: {
      files: [
        {
          expand: true,
          cwd: 'bower_components/',
          src: ['**/*.html'],
          dest: 'build/bower_components/'
        }
      ]
    }
  }
});

The "minifyPolymerCSS" task

Minifies CSS, works with Polymer CSS rules/selectors.

Overview

In your project's Gruntfile, add a section named minifyPolymerCSS ot the data object passed into grunt.initConfig().

grunt.initConfig({
  minifyPolymerCSS: {
    your_target: {
      // Target-specific file lists go here.
    }
  }
});

Options

No options currently available for this task.

Usage Examples

Static File Bindings

grunt.initConfig({
  minifyPolymerCSS: {
    default: {
      files: {
        'dest/my-element.css': 'src/my-element.css',
        'dest/my-other-element.css': 'src/my-other-element.css'
      }
    }
  }
});

Dynamic File Bindings

grunt.initConfig({
  minifyPolymerCSS: {
    default: {
      files: [
        {
          expand: true,
          cwd: 'src/stylesheets/',
          src: ['**/*.css'],
          dest: 'build/'
        }
      ]
    }
  }
});

Minify Polymer-Elements CSS from Bower

grunt.initConfig({
  minifyPolymerCSS: {
    default: {
      files: [
        {
          expand: true,
          cwd: 'bower_components/',
          src: ['**/*.css'],
          dest: 'build/bower_components/'
        }
      ]
    }
  }
});

Suggestions

Use with grunt-vulcanize to minify your Polymer App.

grunt.initConfig({
  minifyPolymer: {
    default: {
      files: [
        {
          expand: true,
          cwd: 'bower_components/',
          src: ['**/*.html'],
          dest: 'build/bower_components/'
        }
      ]
    }
  },
  minifyPolymerCSS: {
    default: {
      files: [
        {
          expand: true,
          cwd: 'bower_components/',
          src: ['**/*.css'],
          dest: 'build/bower_components/'
        }
      ]
    }
  },
  vulcanize: {
    default: {
      files: {
        // Where index.html includes bower_components imports
        'build/build.html': 'build/index.html'
      }
    }
  }
});

grunt.registerTask('default', ['minifyPolymer', 'minifyPolymerCSS', 'vulcanize']);

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.

Pull Requests will be built, using the test suite, on Travis-CI.

License

Copyright (c) 2015 Kevin Kwan. Licensed under the MIT license.

Credits

HTML Minification: Minimize

CSS Minification: Some Regex strings...

JS Minification: UglifyJS

Test Source Files: PolymerElements, Bootstrap