Haml Coffee Assets

Haml Coffee Assets compiles Haml Coffee templates in the Rails 3.1 asset pipeline, so you can use them as JavaScript templates in your JavaScript heavy Rails application. It also works as Tilt template without Rails.

Tested on MRI Ruby 1.8.7, 1.9.2, 1.9.3, REE and the latest version of JRuby.

Haml Coffee

Haml Coffee allows you to write inline CoffeeScript in your HAML JavaScript templates:

#cart
  %h2= I18n.t('js.cart.title')
  - if @cart.length == 0
    %p.empty= I18n.t('js.cart.empty')
  - else
    %ul
      - for item in @cart
        %li
          .item
            = item.name
            %a{ :href => "/cart/item/remove/#{ item.id }" }
              = I18n.t('js.cart.item.remove')

Please note that the I18n object in the above example is not part ot Haml Coffee Assets, the internationalization functions are provided by the i18n.js library.

Installation

The simplest way to install Haml Coffee Assets is to use Bundler. Add haml_coffee_assets and execjs to your Gemfile:

group :assets do
  gem 'haml_coffee_assets'
  gem 'execjs'
end

And require the hamlcoffee.js in your app/assets/javascripts/application.js.coffee:

#= require hamlcoffee

This provides the default escaping and the global context functions. Read more about it in the configuration section below.

Please have a look at the CHANGELOG when upgrading to a newer Haml Coffee Assets version.

Usage

Haml Coffee Assets allows two different ways of generating your JavaScript templates:

Sprocket JST processor template generation

Extension: .jst.hamlc

When you give your templates the extension .jst.hamlc, Haml Coffee Assets will only generate the template function, which then in turn will be further processed by the Sprocket JST processor. Because Haml Coffee Assets will not generate the template, you can't use the template name filter and the JST namespace definition is more cumbersome compared to the Haml Coffee template generation.

With this approach you should place all your Haml Coffee templates in the app/assets/templates directory and include all templates from your app/assets/javascripts/application.js.coffee:

#= require_tree ../templates

If you would place your templates into app/assets/javascripts/templates, then all your JST template names would begin with templates/, which may be not what you want.

Haml Coffee template generation

Extension: .hamlc

If you omit the .jst and give your templates only a .hamlc extension, then Haml Coffee Assets will handle the JavaScript template generation. With this approach you can easily define your own namespace with a simple configuration and you can use the template name filter.

You can place all your Haml Coffee templates in the app/assets/javascripts/templates directory and include all templates from your app/assets/javascripts/application.js.coffee:

#= require_tree ./templates

Because Haml Coffee Assets provides a default template name filter, the templates/ prefix will be automatically removed.

Configuration

Please note that all configuration examples will use the paths of the Haml Coffee template generation and not the Sprocket JST processor template generation.

Sprockets will cache your templates after compiling and will only recompile them when the content of the template has changed, thus if you change to your configuration, the new settings will not be applied to templates already compiled. You can clear the Sprockets cache with:

rake assets:clean

Document format

By default all Haml Coffee templates are rendered to a HTML5 document. You can choose between the following output formats:

html5
html4
xhtml

If you prefer another HTML format than HTML5, you can set it in your config/application.rb:

config.hamlcoffee.format = 'xhtml'

Template namespace

By default all Haml Coffee templates are registered under the JST namespace. A template app/assets/javascripts/templates/header.hamlc with the given content:

%header
  %h2= @title

will be accessible in your browser as JST['header']. You can now render the precompiled template and pass the data to be rendered:

JST['header']({ title: 'Hello Haml Coffee' })

If you prefer another namespace, you can set it in your config/application.rb:

config.hamlcoffee.namespace = 'window.HAML'

You can even set a deep nested namespace like window.templates.HAML and Haml Coffee will handle creation all the way down.

You can't use this configuration if you give your templates a .jst.hamlc extension, because the Sprockets JST processor handles the template generation. In this case you have to subclass the JST processor:

class MyJstProcessor < Sprockets::JstProcessor
  def prepare
    @namespace = 'MyApp.Tpl'
  end
end

Foo::Application.assets.register_engine '.jst', MyJstProcessor

And you must make sure MyApp exists before any template is loaded.

Template name

The name under which the template can be addressed in the namespace depends not only from the filename, but also on the directory name by default.

The following examples assumes a configured namespace window.JST and the asset template directory app/assets/javascripts/templates:

app/assets/javascripts/templates/login.hamlc will become JST['login']
app/assets/javascripts/templates/users/new.hamlc will become JST['users/new']
app/assets/javascripts/templates/shared/form/address.hamlc will become JST['shared/form/address']

Template name filter

If you wish to put the templates in a different location, you may want to modify name_filter in an initializer.

HamlCoffeeAssets::HamlCoffeeTemplate.name_filter = lambda { |n| n.sub /^templates\//, '' }

By default, name_filter strips the leading templates/ directory off of the name. Please note, name_filter is only applicable if you use the .hamlc extension and let Haml Coffee Assets handle the JST generation. If you use the .jst.hamlc extension, then Sprockets JST processor will name things accordingly (e.g., with templates/ intact in this case).

Basename

If you don't want to have your directory names under which your template is located to be contained in the JST name, you can configure Haml Coffee in your config/application.rb to strip off the path to the file name and only use the basename as JST name:

config.hamlcoffee.basename = true

With this setting enabled the following naming rule applies:

app/assets/javascripts/templates/login.hamlc will become JST['login']
app/assets/javascripts/templates/users/new.hamlc will become JST['new']
app/assets/javascripts/templates/shared/form/address.hamlc will become JST['address']

This setting has only an effect when you're using Haml Coffee to generate the JST and not when using the Sprockets JST processor.

Escaping

All generated output by running CoffeeScript in your template is being escaped, but you can disable escaping of either the attributes or the generated Html.

Attribute escaping

You can toggle attribute escaping in your config/application.rb:

config.hamlcoffee.escapeAttributes = false

HTML escaping

You can toggle HTML escaping in your config/application.rb:

config.hamlcoffee.escapeHtml = false

Clean values

Every value that is returned from inline CoffeeScript will be cleaned by default. The included implementation converts null and undefined to an empty string. You can disable value cleaning in your config/application.rb:

config.hamlcoffee.cleanValue = false

Uglify generated HTML

By default all generated HTML is indented to have a nice reading experience. If you like to ignore indention to have a better rendering performance, you can enable the uglify option in your config/application.rb:

config.hamlcoffee.uglify = true

Global context

Haml Coffee Assets allows you to configure a global context function that gets merged into the local template context for each template.

There is a example implementation provided in the hamlcoffee.js that can use the extend like functions from the listed frameworks to merge the global and the local conext data:

jQuery
Underscore.js
Prototype
MooTools
Zepto.js

If you use one of these, than you can simply override HAML.globals and return the global context data:

HAML.globals = ->
  {
    isAuthenticated: App.isAuthenticated()
    isAdmin: App.currentUser.hasRole('admin')
  }

Now you can use the properties from the global context in every template:

.not-found-error
  %h1= I18n.t('js.app.notfound.error', { route: @route })
  - if @isAuthenticated
    %p= I18n.t('js.app.notfound.homepage')
  - else
    %p= I18n.t('js.app.notfound.login')

If you like to use your own implementation, simply configure your context function in your config/application.rb:

config.hamlcoffee.context = 'App.globalTemplateContext'

or disable the global context completely:

config.hamlcoffee.context = false

Your custom context function must take the local context as parameter and returns the merged context data. The following example uses the _.underscore extend function to merge the global context data with the passed local context data:

App.globalTemplateContext = (locals) -> _.extend({}, {
    authenticated: App.isAuthenticated()
}, locals)

Please have a look at the wiki for further examples on how to use the global context.

Customize the tag lists

Haml Coffee contains two list of HTML tags that you can customize. In general you're fine with the defaults, but if you need to extend the list, you can instruct Haml Coffee Assets to do so.

Tags: textarea, pre

Some HTML tags are whitespace sensitive, which means that whitespace used for proper indention results in a wrong display of the tag. In order to avoid this, the content is preserved by converting the newlines to a HTML entity. You can set your own list of whitespace sensitive tags in your config/application.rb:

config.hamlcoffee.preserve = 'pre,textarea,abbr'

This list is also taken into account for the HAML.preserveAndFind helper function that is provided and its shortcut notation ~.

Tags: meta, img, link, br, hr, input, area, param, col, base

The auto-closing tag list will contains the tags that will be self-closes if they have no content. You can set the list of self closing tags in your config/application.rb:

config.hamlcoffee.autoclose = 'meta,img,link,br,hr,input,area,param,col,base'

Custom helper functions

Haml Coffee Assets provides a set of custom functions for Haml Coffee, so that the templates doesn't have to be self contained and can make use of the global functions. In general you don't have to customize them further, but if you need to, you can set custom functions for:

config.hamlcoffee.customHtmlEscape
config.hamlcoffee.customCleanValue
config.hamlcoffee.customPreserve
config.hamlcoffee.customFindAndPreserve
config.hamlcoffee.customSurround
config.hamlcoffee.customSucceed
config.hamlcoffee.customPrecede

You can see the default implementation and the Haml Coffee documentation for more information about each helper function.

Shameless self promotion

Developed by Michael Kessler, sponsored by mksoft.ch.

If you like Haml Coffee Assets, you can watch the repository at GitHub and follow @netzpirat on Twitter for project updates.

Development

Issues and feature request hosted at GitHub Issues.
Documentation hosted at RubyDoc.
Source hosted at GitHub.

Pull requests are very welcome! Please try to follow these simple rules if applicable:

Please create a topic branch for every separate change you make.
Make sure your patches are well tested. All specs must pass.
Update the Yard documentation.
Update the README.
Update the CHANGELOG for noteworthy changes.
Please do not change the version number.

For questions please join #haml on irc.freenode.net

Contributors

See the CHANGELOG and the GitHub list of contributors.

Acknowledgement

Jeremy Ashkenas for CoffeeScript, that little language that compiles into JavaScript.
The people at 9elements who gave us haml-coffee, an elegant JavaScript template solution.

License

(The MIT License)

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the 'Software'), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.