Jade - template engine

Jade is a high performance template engine heavily influenced by Haml and implemented with JavaScript for node.

Features

high performance parser
great readability
code is escaped by default for security
contextual error reporting at compile & run time
executable for compiling jade templates via the command line
formatted output option
html 5 mode (using the !!! 5 doctype)
optional memory caching
combine dynamic and static tag classes
parse tree manipulation via filters
supports Express JS out of the box
transparent iteration over objects, arrays, and even non-enumerables via - each
no tag prefix
filters
- :sass must have sass.js installed
- :less must have less.js installed
- :markdown must have markdown-js installed or node-discount
- :cdata
- :javascript
- :coffeescript must have coffee-script installed
Vim Syntax
TextMate Bundle
Screencasts

Implementations

Installation

via npm:

npm install jade

Public API

var jade = require('jade');

// Render a string
jade.render('string of jade', { options: 'here' });

// Render a file
jade.renderFile('path/to/some.jade', { options: 'here' }, function(err, html){
    // options are optional,
    // the callback can be the second arg
});

Options

scope Evaluation scope (this)
locals Local variable object
filename Used in exceptions, and required by cache
cache Cache intermediate JavaScript in memory keyed by filename
debug Outputs tokens and function body generated
compiler Compiler to replace jade's default

Syntax

Line Endings

CRLF and CR are converted to LF before parsing.

Indentation

Jade is indentation based, however currently only supports a 2 space indent. Tabs are converted to 2 spaces before they hit the lexer.

Tag Text

Simply place some content after the tag:

p wahoo!

renders <p>wahoo!</p>.

well cool, but how about large bodies of text:

p
  | foo bar baz
  | rawr rawr
  | super cool
  | go jade go

renders <p>foo bar baz rawr.....</p>

interpolation? yup! both types of text can utilize interpolation, if we passed { locals: { name: 'tj', email: 'tj@vision-media.ca' }} to render() we can do the following:

#user #{name} &lt;#{email}&gt;

outputs <div id="user">tj <tj@vision-media.ca></div>

Actually want #{} for some reason? escape it!

p \#{something}

now we have <p>#{something}</p>

We can also utilize the unescaped variant !{html}, so the following will result in a literal script tag:

- var html = "<script></script>"
| !{html}

Nested tags that also contain text can optionally use a text block:

label
  | Username:
  input(name='user[name]')

or immediate tag text:

label Username:
  input(name='user[name]')

Comments

Single line comments currently look the same as JavaScript comments, aka "//" and must be placed on their own line:

// just some paragraphs
p foo
p bar

would output

<!-- just some paragraphs -->
<p>foo</p>
<p>bar</p>

Jade also supports unbuffered comments, by simply adding a hyphen:

//- will not output within markup
p foo
p bar

outputting

<p>foo</p>
<p>bar</p>

Nesting

ul
  li one
  li two
  li three

Messed up your whitespace? no worries, jade's error reporting should help you out. Jade instruments the compiled JavaScript to provide meaningful context for runtime exceptions.

ul
    li one
  li two

Error: /Users/tj/Projects/jade/examples/layout.jade:2
    1. 'ul'
    2. '    li one'

Invalid indentation, got 2 expected 1.

Note: Trailing outdents are generated on EOS (end-of-source) if not present.

Attributes

Jade currently supports '(' and ')' as attribute delimiters.

a(href='/login', title='View login page') Login

Alternatively we may use the colon to separate pairs:

a(href: '/login', title: 'View login page') Login

Boolean attributes are also supported:

input(type="checkbox", checked)

Boolean attributes with code will only output the attribute when true:

input(type="checkbox", checked: someValue)

Note: Leading / trailing whitespace is ignored for attr pairs.

Doctypes

To add a doctype simply use !!! followed by an optional value:

!!!

Will output the transitional doctype, however:

!!! 5

Will output html 5's doctype. Below are the doctypes defined by default, which can easily be extended: var doctypes = exports.doctypes = { '5': '', 'xml': '', 'default': '', 'transitional': '', 'strict': '', 'frameset': '', '1.1': '', 'basic': '', 'mobile': '' };

To alter the default simply change:

jade.doctypes.default = 'whatever you want';

Filters

Filters are prefixed with :, for example :markdown and pass the following block of text to an arbitrary function for processing. View the features at the top of this document for available filters.

body
  :markdown
    | Woah! jade _and_ markdown, very **cool**
    | we can even link to [stuff](http://google.com)

Renders:

   <body><p>Woah! jade <em>and</em> markdown, very <strong>cool</strong> we can even link to <a href="http://google.com">stuff</a></p></body>

Filters may also now manipulate the parse tree. For example perhaps I want to bake conditionals right into jade, we could do so with a filter named conditionals. Typically filters work on text blocks, however by passing a regular block our filter can do anything it wants with the tags nested within it.

body
  :conditionals
    if role == 'admin'
      p You are amazing
    else
      p Not so amazing

Not that we no longer prefix with "-" for these code blocks. Examples of how to manipulate the parse tree can be found at ./examples/conditionals.js and ./examples/model.js. There are several interesting use-cases for this functionality above what was shown above such as transparently aggregating / compressing assets to reduce the number of HTTP requests, transparent record error reporting, and more.

Code

Jade currently supports three classifications of executable code. The first is prefixed by -, and is not buffered:

- var foo = 'bar';

This can be used for conditionals, or iteration:

- for (var key in obj)
  p= obj[key]

Due to Jade's buffering techniques the following is valid as well:

- if (foo)
  ul
    li yay
    li foo
    li worked
- else
  p oh no! didnt work

Hell, even verbose iteration:

- if (items.length)
  ul
    - items.forEach(function(item){
      li= item
    - })

Anything you want!

Next up we have escaped buffered code, which is used to buffer a return value, which is prefixed by =:

- var foo = 'bar'
= foo
h1= foo

Which outputs bar<h1>bar<h1/>. Code buffered by = is escaped by default for security, however to output unescaped return values you may use !=:

p!= aVarContainingMoreHTML

The on exception made in terms of allowing "vanilla" JavaScript, is the - each token. This takes the form of:

- each VAL[, KEY] in OBJ

An example iterating over an array:

- var items = ["one", "two", "three"]
- each item in items
  li= item

outputs:

<li>one</li>
<li>two</li>
<li>three</li>

iterating an object's keys and values:

- var obj = { foo: 'bar' }
- each val, key in obj
  li #{key}: #{val}

would output <li>foo: bar</li>

You can also nest these!

- each user in users
  - each role in user.roles
    li= role

bin/jade

Output html to stdout:

jade examples/*.jade --pipe

Generate examples/*.html:

jade examples/*.jade

Pass options:

jade examples/layout.jade --options '{ locals: { title: "foo" }}'

Usage info:

�Usage: jade [options] <path ...>

�Options:
  -o, --options STR   JavaScript options object passed
  -p, --pipe          Output to stdout instead of PATH.html
  -h, --help          Output help information

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.

sebm/jade