Haml Coffee is a JavaScript templating solution that uses Haml as markup, understands inline CoffeeScript and generates a JavaScript function that renders to HTML. It can be used in client-side JavaScript applications that are using Backbone.js, Spine.js, JavaScriptMVC, KnockoutJS and others, or on the server-side in frameworks like Express.
You can try Haml Coffee online by visiting Haml Coffee Online.
Haml Coffee is available in NPM and can be installed with:
$ npm install haml-coffee
Please have a look at the CHANGELOG when upgrading to a
newer Codo version with npm update
.
If you're using Hem to manage your CommonJS modules, use hem-haml-coffee. This is excellent for developing your Spine application.
If you like to integrate Haml Coffee seamless into the Rails asset pipeline, check out haml_coffee_assets.
For using the Haml Coffee compiler in the browser, a browserified version
is provided in the dist/compiler
directory:
Haml Coffee compiler
(minified)
You can compile a Haml Coffee template to a JavaScript function and execute the function with the locals to render the HTML. The following code
hamlc = require 'haml-coffee'
tmpl = hamlc.compile '%h1= @title'
html = tmpl title: 'Haml Coffee rocks!'
will create the HTML <h1>Haml Coffee rocks!</h1>
.
The compile
function can take the compiler options as second parameter to customize the template function:
hamlc.compile '%h1= @title'
cleanValue: false
escapeHtml: false
See the compiler options for detailed information about all the available options and browse the codo generated Haml-Coffee API documentation.
You can configure Express to use Haml Coffee as template engine.
Starting with version 1.4.0, Haml Coffee has support for Express 3 and can be registered as view engine as follows:
express = require 'express'
app = express()
app.engine 'hamlc', require('haml-coffee').__express
Alternatively you can also use consolidate.js to register the engine:
express = require 'express'
cons = require 'consolidate'
app = express()
app.engine 'hamlc', cons['haml-coffee']);
Starting with version 0.5.0, Haml Coffee has support for Express 2 and can be registered as view engine as follows:
express = require 'express'
app = express.createServer()
app.register '.hamlc', require('haml-coffee')
Alternatively you can also use consolidate.js to register the engine:
express = require 'express'
cons = require 'consolidate'
app = express.createServer()
app.register '.hamlc', cons['haml-coffee']
Express uses a layout file layout.hamlc
by default and you have to insert the rendered view body into the layout like
this:
!!!
%head
%title Express App
%body
!= @body
Now you can create a Haml Coffee view
%h1= "Welcome #{ @name }"
%p You've rendered your first Haml Coffee view.
that you can render with:
app.get '/', (req, res) ->
res.render 'index.hamlc', name: 'Express user'
It's possible to use Haml Coffee as the default template engine by setting the view engine
:
app.configure ->
app.set 'view engine', 'hamlc'
which allows you to omit the .hamlc
extension when rendering a template:
app.get '/', (req, res) ->
res.render 'index', name: 'Express user'
With Express 3, you can set global compiler options by using app.locals
:
app.locals.uglify = true
which is the same as:
res.render view, { uglify: true }
See the compiler options for detailed information about all the available options.
After the installation you will have a haml-coffee
binary that can be used to compile single templates and even
compile multiple templates recursively into a single file.
$ haml-coffee
Usage: node haml-coffee
Options:
-i, --input Either a file or a directory name to be compiled
-o, --output Set the output filename
-n, --namespace Set a custom template namespace
-t, --template Set a custom template name
-b, --basename Ignore file path when generate the template name
-e, --extend Extend the template scope with the context
The following section describes only the options that are unique to the command line tool.
You can see all the available options by executing haml-coffee --help
and have a look at the
compiler options for detailed information about all the options.
You can either specify a single template or a directory with the -i
/--input
argument. When you supply a directory,
templates are being searched recursively:
$ haml-coffee -i template.haml
This will generate a template with the same name as the file but the extension changed to .jst
. The above command for
example would generate a template named template.jst
.
A valid Haml Coffee template must have one of the following extensions: .haml
, .html.haml
, .hamlc
or
.html.hamlc
.
You can specify a single output file name to be used instead of the automatic generated output file name with the
-o
/--output
argument:
$ haml-coffee -i template.haml -o t.js
This creates a template named t.js
. You can also set a directory as input and give an output file name for
concatenating all templates into a single file:
$ haml-coffee -i templates -o all.js
This will create all the templates under the templates
directory into a single, combined output file all.js
.
Each template will register itself by default under the window.HAML
namespace, but you can change the namespace with
the -n
/--namespace
argument:
$ haml-coffee -i template.haml -n exports.JST
Each template must have a unique name under which it can be addressed. By default the template name is derived from the
template file name by stripping off all extensions and remove illegal characters. Directory names are converted to
nested namespaces under the default namespace. For example, a template named user/show-admin.html.haml
will result in
a template that can be accessed by window.HAML['user/show_admin']
.
Given the -b
/--basename
argument, the deduced template name will not include the path to the template. For example,
a template named user/show-admin.html.haml
will result in a template that can be accessed by
window.HAML['show_admin']
instead of window.HAML['user/show_admin']
.
With the -t
/--template
argument you can set a template name manually:
$ haml-coffee -i template.haml -n exports.JST -t other
This will result in a template that can be accessed by exports.JST['other']
.
By extending the template scope with the context, you can access your context data without @
or this
:
%h2= title
This effect is achieved by using the with statement. Using with is forbidden in ECMAScript 5 strict mode.
Haml Coffee implements the Haml Spec to ensure some degree of compatibility to other Haml implementations and the following sections are fully compatible to Ruby Haml:
- Plain text
- Multiline:
|
- Element names
%
- Attributes:
{}
or()
- Class and ID:
.
and#
, implicitdiv
elements - Self-closing tags:
/
- Doctype:
!!!
- HTML comments:
/
, conditional comments:/[]
, Haml comments:-#
- Running CoffeeScript:
-
, inserting CoffeeScript:=
- CoffeeScript interpolation:
#{}
- Whitespace preservation:
~
- Whitespace removal:
>
and<
- Escaping
\
- Escaping HTML:
&=
, unescaping HTML:!=
- Filters:
:plain
,:javascript
,:css
,:cdata
,:escaped
,:preserve
- Boolean attributes conversion
Please consult the official Haml reference for more details.
Haml Coffee supports both Ruby 1.8 and Ruby 1.9 style attributes. So the following Ruby 1.8 style attribute
%a{ :href => 'http://haml-lang.com/' } Haml
can also be written in Ruby 1.9 style:
%a{ href: 'http://haml-lang.com/' } Haml
Haml Coffee supports a small subset of the Ruby Haml helpers:
Surrounds a block of Haml code with strings, with no whitespace in between.
= surround '(', ')', ->
%a{:href => "food"} chicken
produces the HTML output
(<a href='food'>chicken</a>)
Appends a string to the end of a Haml block, with no whitespace between.
click
= succeed '.', ->
%a{:href=>"thing"} here
produces the HTML output
click
<a href='thing'>here</a>.
Prepends a string to the beginning of a Haml block, with no whitespace between.
= precede '*', ->
%span.small Not really
produces the HTML output
*<span class='small'>Not really</span>
Haml and CoffeeScript are a winning team, both use indention for blocks and are a perfect match for this reason. You can use CoffeeScript instead of Ruby in your Haml tags and the attributes.
It's not recommended to put too much logic into the template.
When you define an attribute value without putting it into quotes (single or double quotes), it's considered to be CoffeeScript code to be run at render time. By default, attributes values from CoffeeScript code are escaped before inserting into the document. You can change this behaviour by setting the appropriate compiler option.
HTML style attributes are the most limited and can only assign a simple variable:
%img(src='/images/demo.png' width=@width height=@height alt=alt)
Both the @width
and @height
values must be passed as locals when rendering the template and alt
must be defined
before the %img
tag.
Ruby style tags can be more complex and can call functions:
%header
%user{ :class => App.currentUser.get('status') }= App.currentUser.getDisplayName()
Attribute definitions are also supported in the Ruby 1.9 style:
%header
%user{ class: App.currentUser.get('status') }= App.currentUser.getDisplayName()
More fancy stuff can be done when use interpolation within a double quoted attribute value:
%header
%user{ class: "#{ if @user.get('roles').indexOf('admin') is -1 then 'normal' else 'admin' }" }= @user.getDisplayName()
But think about it twice before putting such fancy stuff into your template, there are better places like models, controllers or helpers to put heavy logic into.
You can define your attributes over multiple lines and the next line must not be correctly indented, so you can align them properly:
%input#password.hint{ type: 'password', name: 'registration[password]',
data: { hint: 'Something very important', align: 'left' } }
In the above example you also see the usage for generating HTML5 data attributes.
You can run any CoffeeScript code in your template:
- for project in @projects
- if project.visible
.project
%h1= project.name
%p&= project.description
There are several supported types to run your code:
- Run code without insert anything into the document:
-
- Run code and insert the result into the document:
=
All inserted content from running code is escaped by default. You can change this behaviour by setting the appropriate compiler option.
There are three variations to run code and insert its result into the document, two of them to change the escaping style chosen in the compile option:
- Run code and do not escape the result:
!=
- Run code and escape the result:
&=
- Preserve whitespace when insert the result:
~
Again, please consult the official Haml reference for more details. Haml Coffee implements the same functionality like Ruby Haml, only for CoffeeScript.
Running code must be placed on a single line and unlike Ruby Haml, you cannot stretch a it over multiple lines by putting a comma at the end.
However, you can use multiline endings |
to stretch your code over multiple lines to some extend:
- links = { |
home: '/', |
docs: '/docs', |
about: '/about' |
} |
%ul
- for name, link of links
%li
%a{ href: link }= name
Please note, that since the line is concatenated before the compilation, you cannot omit the curly braces and the commas in the above example, like you'd do in normal CoffeeScript code. Therefore it's recommended to use the CoffeeScript filter to have real multiline code blocks:
:coffeescript
links =
home: '/'
docs: '/docs'
about: '/about'
%ul
- for name, link of links
%li
%a{ href: link }= name
You can also create functions that generate Haml:
- sum = (a, b) ->
%div
%span= a
%span= b
%span= a+b
= sum(1,2)
= sum(3,4)
or pass generated HTML output through a function for post-processing.
= postProcess ->
%a{ href: '/' }
The content of the :coffeescript
filter is run when the template is rendered and doesn't output anything into the
resulting document. This comes in handy when you have code to run over multiple lines and don't want to prefix each line
with -
:
%body
:coffeescript
tags = ['CoffeeScript', 'Haml']
project = 'Haml Coffee'
%h2= project
%ul
- for tag in tags
%li= tag
The following section describes all the available compiler options that you can use through the JavaScript API, as Express view option or as argument to the command line utility.
The command line arguments may be slightly different. For example instead of passing --escape-html=false
you have to
use the --disable-html-escaping
argument. You can see a list of all the command line arguments by executing
haml-coffee --help
.
The HTML options change the way how the generated HTML will look like.
- Name: 'format'
- Type:
String
- Default:
html5
The Haml parser knows different HTML formats to which a given template can be rendered and it must be one of:
- xhtml
- html4
- html5
Doctype, self-closing tags and attributes handling depends on this setting. Please consult the official Haml reference for more details.
- Name:
uglify
- Type:
Boolean
- Default:
false
All generated HTML tags are properly indented by default, so the output looks nice. This can be helpful when debugging.
You can skip the indention by setting the uglify
option to false. This save you some bytes and you'll have increased
rendering speed.
- Name:
htmlEscape
- Type:
Boolean
- Default:
true
The reserved HTML characters "
, '
, &
, <
and >
are converted to their HTML entities by default when they are
inserted into the HTML document from evaluated CoffeeScript.
You can always change the escaping mode within the template to either force escaping with &=
or force unescaping with
!=
.
- Name:
escapeAttributes
- Type:
Boolean
- Default:
true
All HTML attributes that are generated by evaluating CoffeeScript are also escaped by default. You can turn of HTML
escaping of the attributes only by setting escapeAttributes
to false. You can't change this behaviour in the template
since there is no Haml markup for this to instruct the compiler to change the escaping mode.
- Name:
cleanValue
- Type:
Boolean
- Default:
true
Every output that is generated from evaluating CoffeeScript code is cleaned before inserting into the document. The
default implementation converts null
or undefined
values into an empty string and marks real boolean values with a
hidden marker character. The hidden marker character is necessary to distinguish between String values like 'true'
,
'false'
and real boolean values true
, false
in the markup, so that a boolean attribute conversion can quickly
convert these values to the correct HTML5/XHTML/HTML4 representation.
- Name:
preserve
- Type:
String
- Default:
textarea,pre
The preserve
option defines a list of comma separated HTML tags that are whitespace sensitive. Content from these tags
must be preserved, so that the indention has no influence on the displayed content. This is simply done by converting
the newline characters to their equivalent HTML entity.
- Name:
autoclose
- Type:
String
- Default:
meta,img,link,br,hr,input,area,param,col,base
The autoclose option defines a list of tag names that should be automatically closed if they have no content.
Haml Coffee provides helper functions for HTML escaping, value cleaning and whitespace preservation, which must be available at render time. By default every generated template function is self-contained and includes all of the helper functions.
However you can change the reference to each helper function by providing the appropriate compiler option and there are good reasons to do so:
- You want to reduce the template size and provide all the helpers from a central place.
- You want to customize a helper function to better fit your needs.
To change these functions, simply assign the new function name to one of the following options:
customHtmlEscape
: Escape the reserved HTML characters into their equivalent HTML entity.customPreserve
: Converting newlines into their HTML entity.customFindAndPreserve
: Find whitespace sensitive tags and preserve their content.customCleanValue
: Clean the value that is returned after evaluating some inline CoffeeScript.customSurround
: Surrounds a block of Haml code with strings, with no whitespace in between.customSucceed
: Appends a string to the end of a Haml block, with no whitespace between.customPrecede
: Prepends a string to the beginning of a Haml block, with no whitespace between.
You can find a default implementation for all these helper functions in Haml Coffee Assets.
Haml-Coffee uses Guard for development, which you can install Guard with the Ruby Bundler:
$ bundle install
Install the Node modules with NPM:
$ npm install
and run Guard to automatically compile your CoffeeScripts and run the Jasmine specs on file modification:
$ bundle exec guard
Feel free to take a look at the crispy changelog instead of crawling through the commit history.
Haml Coffee in the Rails asset pipeline:
- Michael Kessler (@netzpirat, mksoft.ch)
- Sebastion Deutsch (@sippndipp, 9elements)
- Jan Varwig (@agento, 9elements)
See all contributors on the contributor page.
(The MIT License)
Copyright (c) 2011-2012 9elements, Michael Kessler
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.