svg_sprite_helper.rb

# Usage:
# <%= svg_sprites(Rails.root.join('app/assets/images/sprites/*.svg')) %>
# <%= svg_icon('icon--check-circle') %>

module SvgSpriteHelper

  def svg_icon(icon, options={})
    options[:class] ||= []
    options[:class]   = [icon] + options[:class].split(' ')
    
    content_tag(:svg, options) do
      content_tag(:use, nil, 'xlink:href'=>"##{icon}")
    end
  end

  def svg_sprites(sprites, prefix=nil)
    content_tag(:svg, style:'display:none') do
      Dir.glob(sprites).each do |svg_file|
        concat svg_to_symbol(svg_file, prefix)
      end
    end
  end

  def svg_to_symbol(svg_file, prefix=nil)
    svg_doc   = Nokogiri::HTML(open(svg_file)) { |config| config.noblanks }

    # Fetch attributes
    svg       = svg_doc.at_css('svg')
    icon_name = svg_file.gsub('.svg', '').split('/').last
    icon_id   = [prefix, icon_name].compact.join('/')
    
    # Get icon
    icon_data = svg.at_css("[id^='#{icon_id}']")
    icon_data.remove_attribute('id')
        
    content_tag(:symbol, icon_data.to_html.html_safe, { id: icon_name, viewBox: svg['viewbox'] })
  end

end