Contents

=begin
Copyright 2013 Andrey “A.I.” Sitnik <[e-mail]>,
sponsored by Evil Martians.

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.
=end

require 'execjs'

module AutoprefixerRails
  # Ruby to JS wrapper for Autoprefixer compiler instance
  class Compiler
    def initialize(browsers)
      @browsers = browsers || []
    end

    # Return prefixed `css`
    def compile(css)
      compiler.call('compile', css)
    end

    # Return, which browsers and prefixes will be used
    def inspect
      compiler.call('inspect')
    end

    # Lazy load for JS instance
    def compiler
      @compiler ||= ExecJS.compile(build_js)
    end

    private

    # Cache autoprefixer.js content
    def read_js
      @@js ||= Pathname(__FILE__).join("../../../vendor/autoprefixer.js").read
    end

    # Return compiler JS with some extra methods
    def build_js
      read_js + create_instance + add_proxy('compile') + add_proxy('inspect')
    end

    # Return JS code to create Autoprefixer instance
    def create_instance
      if @browsers.empty?
        "var compiler = autoprefixer;"
      else
        browsers = @browsers.map(&:to_s).join("', '")
        "var compiler = autoprefixer('#{browsers}');"
      end
    end

    # Return JS code to create proxy methods
    def add_proxy(func)
      <<-JS
        var #{ func } = function() {
          return compiler.#{ func }.apply(compiler, arguments)
        };
      JS
    end
  end
end

Version data entries

2 entries across 2 versions & 1 rubygems

Version	Path
autoprefixer-rails-0.6.20130721	lib/autoprefixer-rails/compiler.rb
autoprefixer-rails-0.6.20130716	lib/autoprefixer-rails/compiler.rb