Jade - template engine

Jade is a high performance template engine heavily influenced by Haml and implemented with JavaScript for node. For discussion join the Google Group.

Announcement

Jade version 0.31.0 deprecated implicit text only support for scripts and styles. To fix this all you need to do is add a . character after the script or style tag.

It is hoped that this change will make Jade easier for newcomers to learn without affecting the power of the language or leading to excessive verboseness.

If you have a lot of Jade files that need fixing you can use fix-jade to attempt to automate the process.

Test drive

You can test drive Jade online here.

README Contents

• Features
• Implementations
• Installation
• Browser Support
• Public API
• Syntax
  • Line Endings
  • Tags
  • Tag Text
  • Comments
  • Block Comments
  • Nesting
  • Block Expansion
  • Case
  • Attributes
  • HTML
  • Doctypes
• Filters
• Code
• Iteration
• Conditionals
• Template inheritance
• Block append / prepend
• Includes
• Mixins
• Generated Output
• Example Makefile
• jade(1)
• Tutorials
• License

## Features

• client-side support
• great readability
• flexible indentation
• block-expansion
• mixins
• static includes
• attribute interpolation
• code is escaped by default for security
• contextual error reporting at compile & run time
• executable for compiling jade templates via the command line
• html 5 mode (the default doctype)
• optional memory caching
• combine dynamic and static tag classes
• parse tree manipulation via filters
• template inheritance
• block append / prepend
• supports Express JS out of the box
• transparent iteration over objects, arrays, and even non-enumerables via each
• block comments
• no tag prefix
• filters
  • :stylus must have stylus installed
  • :less must have less.js installed
  • :markdown must have markdown-js, node-discount, or marked installed
  • :cdata
  • :coffeescript must have coffee-script installed
• Emacs Mode
• Vim Syntax
• TextMate Bundle
• Coda/SubEtha syntax Mode
• Screencasts
• html2jade converter

## Implementations

• php
• scala
• ruby
• python
• java

## Installation

via npm:

$ npm install jade

## Browser Support

To compile jade to a single file compatible for client-side use simply execute:

$ make jade.js

Alternatively, if uglifyjs is installed via npm (npm install uglify-js) you may execute the following which will create both files. However each release builds these for you.

$ make jade.min.js

By default Jade instruments templates with line number statements such as __.lineno = 3 for debugging purposes. When used in a browser it's useful to minimize this boiler plate, you can do so by passing the option { compileDebug: false }. The following template

p Hello #{name}

Can then be as small as the following generated function:

function anonymous(locals, attrs, escape, rethrow) {
  var buf = [];
  with (locals || {}) {
    var interp;
    buf.push('\n<p>Hello ' + escape((interp = name) == null ? '' : interp) + '\n</p>');
  }
  return buf.join("");
}

Through the use of Jade's ./runtime.js you may utilize these pre-compiled templates on the client-side without Jade itself, all you need is the associated utility functions (in runtime.js), which are then available as jade.attrs, jade.escape etc. To enable this you should pass { client: true } to jade.compile() to tell Jade to reference the helper functions via jade.attrs, jade.escape etc.

function anonymous(locals, attrs, escape, rethrow) {
  var attrs = jade.attrs, escape = jade.escape, rethrow = jade.rethrow;
  var buf = [];
  with (locals || {}) {
    var interp;
    buf.push('\n<p>Hello ' + escape((interp = name) == null ? '' : interp) + '\n</p>');
  }
  return buf.join("");
}

## Public API

var jade = require('jade');

// Compile a function
var fn = jade.compile('string of jade', options);
fn(locals);

Options

• self Use a self namespace to hold the locals (false by default)
• locals Local variable object
• filename Used in exceptions, and required when using includes
• debug Outputs tokens and function body generated
• compiler Compiler to replace jade's default
• compileDebug When false no debug instrumentation is compiled
• pretty Add pretty-indentation whitespace to output (false by default)

## Syntax ### Line Endings

CRLF and CR are converted to LF before parsing.

### Tags

A tag is simply a leading word:

html

for example is converted to <html></html>

tags can also have ids:

div#container

which would render <div id="container"></div>

how about some classes?

div.user-details

renders <div class="user-details"></div>

multiple classes? and an id? sure:

div#foo.bar.baz

renders <div id="foo" class="bar baz"></div>

div div div sure is annoying, how about:

#foo
.bar

which is syntactic sugar for what we have already been doing, and outputs:

<div id="foo"></div><div class="bar"></div>

### 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 { name: 'tj', email: 'tj@vision-media.ca' } to the compiled function we can do the following:

#user #{name} <#{email}>

outputs <div id="user">tj &lt;tj@vision-media.ca&gt;</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]')

As an alternative, we may use a trailing . to indicate a text block, for example:

p.
  foo asdf
  asdf
   asdfasdfaf
   asdf
  asd.

outputs:

<p>foo asdf
asdf
  asdfasdfaf
  asdf
asd.
</p>

This however differs from a trailing . followed by a space, which although is ignored by the Jade parser, tells Jade that this period is a literal:

p .

outputs:

<p>.</p>

It should be noted that text blocks should be doubled escaped. For example if you desire the following output.

<p>foo\bar</p>

use:

p.
  foo\\bar

### 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>

### Block Comments

A block comment is legal as well:

body
  //
    #content
      h1 Example

outputting

<body>
  <!--
  <div id="content">
    <h1>Example</h1>
  </div>
  -->
</body>

Jade supports conditional-comments as well, for example:

head
  //if lt IE 8
    script(src='/ie-sucks.js')

outputs:

<head>
  <!--[if lt IE 8]>
    <script src="/ie-sucks.js"></script>
  <![endif]-->
</head>

### Nesting

Jade supports nesting to define the tags in a natural way:

ul
  li.first
    a(href='#') foo
  li
    a(href='#') bar
  li.last
    a(href='#') baz

### Block Expansion

Block expansion allows you to create terse single-line nested tags, the following example is equivalent to the nesting example above.

ul
  li.first: a(href='#') foo
  li: a(href='#') bar
  li.last: a(href='#') baz

### Case

The case statement takes the following form:

html
  body
    friends = 10
    case friends
      when 0
        p you have no friends
      when 1
        p you have a friend
      default
        p you have #{friends} friends

Block expansion may also be used:

friends = 5

html
  body
    case friends
      when 0: p you have no friends
      when 1: p you have a friend
      default: p you have #{friends} friends

### Attributes

Jade currently supports ( and ) as attribute delimiters.

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

When a value is undefined or null the attribute is not added, so this is fine, it will not compile something="null".

div(something=null)

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)

Multiple lines work too:

input(type='checkbox',
  name='agreement',
  checked)

Multiple lines without the comma work fine:

input(type='checkbox'
  name='agreement'
  checked)

Funky whitespace? fine:

input(
  type='checkbox'
  name='agreement'
  checked)

Colons work:

rss(xmlns:atom="atom")

Suppose we have the user local { id: 12, name: 'tobi' } and we wish to create an anchor tag with href pointing to "/user/12" we could use regular javascript concatenation:

a(href='/user/' + user.id)= user.name

or we could use jade's interpolation, which I added because everyone using Ruby or CoffeeScript seems to think this is legal js..:

a(href='/user/#{user.id}')= user.name

The class attribute is special-cased when an array is given, allowing you to pass an array such as bodyClasses = ['user', 'authenticated'] directly:

body(class=bodyClasses)

### HTML

Inline html is fine, we can use the pipe syntax to write arbitrary text, in this case some html:

html
  body
    | <h1>Title</h1>
    | <p>foo bar baz</p>

Or we can use the trailing . to indicate to Jade that we only want text in this block, allowing us to omit the pipes:

html
  body.
    <h1>Title</h1>
    <p>foo bar baz</p>

Both of these examples yield the same result:

<html><body><h1>Title</h1>
<p>foo bar baz</p>
</body></html>

The same rule applies for anywhere you can have text in jade, raw html is fine:

html
  body
    h1 User <em>#{name}</em>

### Doctypes

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

!!!

or

doctype

Will output the html 5 doctype, however:

!!! transitional

Will output the transitional doctype.

Doctypes are case-insensitive, so the following are equivalent:

doctype Basic
doctype basic

it's also possible to simply pass a doctype literal:

doctype html PUBLIC "-//W3C//DTD XHTML Basic 1.1//EN"

yielding:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML Basic 1.1//EN">

Below are the doctypes defined by default, which can easily be extended:

var doctypes = exports.doctypes = {
  '5': '<!DOCTYPE html>',
  'default': '<!DOCTYPE html>',
  'xml': '<?xml version="1.0" encoding="utf-8" ?>',
  'transitional': '<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">',
  'strict': '<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">',
  'frameset': '<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Frameset//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-frameset.dtd">',
  '1.1': '<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">',
  'basic': '<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML Basic 1.1//EN" "http://www.w3.org/TR/xhtml-basic/xhtml-basic11.dtd">',
  'mobile': '<!DOCTYPE html PUBLIC "-//WAPFORUM//DTD XHTML Mobile 1.2//EN" "http://www.openmobilealliance.org/tech/DTD/xhtml-mobile12.dtd">'
};

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>

## 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

Jade also has designer-friendly variants, making the literal JavaScript more expressive and declarative. For example the following assignments are equivalent, and the expression is still regular javascript:

- var foo = 'foo ' + 'bar'
foo = 'foo ' + 'bar'

Likewise Jade has first-class if, else if, else, until, while, unless among others, however you must remember that the expressions are still regular javascript:

if foo == 'bar'
  ul
    li yay
    li foo
    li worked
else
  p oh no! didnt work

## Iteration

Along with vanilla JavaScript Jade also supports a subset of constructs that allow you to create more designer-friendly templates, one of these constructs is each, taking the form:

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 array with index:

items = ["one", "two", "three"]
each item, i in items
  li #{item}: #{i}

outputs:

<li>one: 0</li>
<li>two: 1</li>
<li>three: 2</li>

iterating an object's keys and values:

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

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

Internally Jade converts these statements to regular JavaScript loops such as users.forEach(function(user){, so lexical scope and nesting applies as it would with regular JavaScript:

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

You may also use for if you prefer:

for user in users
  for role in user.roles
    li= role

## Conditionals

Jade conditionals are equivalent to those using the code (-) prefix, however allow you to ditch parenthesis to become more designer friendly, however keep in mind the expression given is regular JavaScript:

for user in users
  if user.role == 'admin'
    p #{user.name} is an admin
  else
    p= user.name

is equivalent to the following using vanilla JavaScript literals:

for user in users
  - if (user.role == 'admin')
    p #{user.name} is an admin
  - else
    p= user.name

Jade also provides unless which is equivalent to if (!(expr)):

for user in users
  unless user.isAnonymous
    p
      | Click to view
      a(href='/users/' + user.id)= user.name

## Template inheritance

Jade supports template inheritance via the block and extends keywords. A block is simply a "block" of Jade that may be replaced within a child template, this process is recursive. To activate template inheritance in Express 2.x you must add: app.set('view options', { layout: false });.

Jade blocks can provide default content if desired, however optional as shown below by block scripts, block content, and block foot.

html
  head
    h1 My Site - #{title}
    block scripts
      script(src='/jquery.js')
  body
    block content
    block foot
      #footer
        p some footer content

Now to extend the layout, simply create a new file and use the extends directive as shown below, giving the path (with or without the .jade extension). You may now define one or more blocks that will override the parent block content, note that here the foot block is not redefined and will output "some footer content".

extends layout

block scripts
  script(src='/jquery.js')
  script(src='/pets.js')

block content
  h1= title
  each pet in pets
    include pet

It's also possible to override a block to provide additional blocks, as shown in the following example where content now exposes a sidebar and primary block for overriding, or the child template could override content all together.

extends regular-layout

block content
  .sidebar
    block sidebar
      p nothing
  .primary
    block primary
      p nothing

## Block append / prepend

Jade allows you to replace (default), prepend, or append blocks. Suppose for example you have default scripts in a "head" block that you wish to utilize on every page, you might do this:

html
  head
    block head
      script(src='/vendor/jquery.js')
      script(src='/vendor/caustic.js')
  body
    block content

Now suppose you have a page of your application for a JavaScript game, you want some game related scripts as well as these defaults, you can simply append the block:

extends layout

block append head
  script(src='/vendor/three.js')
  script(src='/game.js')

When using block append or block prepend the block is optional:

extends layout

append head
  script(src='/vendor/three.js')
  script(src='/game.js')

## Includes

Includes allow you to statically include chunks of Jade, or other content like css, or html which lives in separate files. The classical example is including a header and footer. Suppose we have the following directory structure:

./layout.jade
./includes/
  ./head.jade
  ./foot.jade

and the following layout.jade:

html
  include includes/head
  body
    h1 My Site
    p Welcome to my super amazing site.
    include includes/foot

both includes includes/head and includes/foot are read relative to the filename option given to layout.jade, which should be an absolute path to this file, however Express does this for you. Include then parses these files, and injects the AST produced to render what you would expect:

<html>
  <head>
    <title>My Site</title>
    <script src="/javascripts/jquery.js">
    </script><script src="/javascripts/app.js"></script>
  </head>
  <body>
    <h1>My Site</h1>
    <p>Welcome to my super lame site.</p>
    <div id="footer">
      <p>Copyright>(c) foobar</p>
    </div>
  </body>
</html>

As mentioned include can be used to include other content such as html or css. By providing an extension, Jade will read that file in, apply any filter matching the file's extension, and insert that content into the output.

html
  head
    //- css and js have simple filters that wrap them in
        <style> and <script> tags, respectively
    include stylesheet.css
    include script.js
  body
    //- "markdown" files will use the "markdown" filter
        to convert Markdown to HTML
    include introduction.markdown
    //- html files have no filter and are included verbatim
    include content.html

Include directives may also accept a block, in which case the the given block will be appended to the last block defined in the file. For example if head.jade contains:

head
  script(src='/jquery.js')

We may append values by providing a block to include head as shown below, adding the two scripts.

html
  include head
    script(src='/foo.js')
    script(src='/bar.js')
  body
    h1 test

You may also yield within an included template, allowing you to explicitly mark where the block given to include will be placed. Suppose for example you wish to prepend scripts rather than append, you might do the following:

head
  yield
  script(src='/jquery.js')
  script(src='/jquery.ui.js')

Since included Jade is parsed and literally merges the AST, lexically scoped variables function as if the included Jade was written right in the same file. This means include may be used as sort of partial, for example suppose we have user.jade which utilizes a user variable.

h1= user.name
p= user.occupation

We could then simply include user while iterating users, and since the user variable is already defined within the loop the included template will have access to it.

users = [{ name: 'Tobi', occupation: 'Ferret' }]

each user in users
  .user
    include user

yielding:

<div class="user">
  <h1>Tobi</h1>
  <p>Ferret</p>
</div>

If we wanted to expose a different variable name as user since user.jade references that name, we could simply define a new variable as shown here with user = person:

each person in users
  .user
    user = person
    include user

## Mixins

Mixins are converted to regular JavaScript functions in the compiled template that Jade constructs. Mixins may take arguments, though not required:

mixin list
  ul
    li foo
    li bar
    li baz

Utilizing a mixin without args looks similar, just without a block:

h2 Groceries
mixin list

Mixins may take one or more arguments as well, the arguments are regular javascripts expressions, so for example the following:

mixin pets(pets)
  ul.pets
    - each pet in pets
      li= pet

mixin profile(user)
  .user
    h2= user.name
    mixin pets(user.pets)

Would yield something similar to the following html:

<div class="user">
  <h2>tj</h2>
  <ul class="pets">
    <li>tobi</li>
    <li>loki</li>
    <li>jane</li>
    <li>manny</li>
  </ul>
</div>

## Generated Output

Suppose we have the following Jade:

- var title = 'yay'
h1.title #{title}
p Just an example

When the compileDebug option is not explicitly false, Jade will compile the function instrumented with __.lineno = n;, which in the event of an exception is passed to rethrow() which constructs a useful message relative to the initial Jade input.

function anonymous(locals) {
  var __ = { lineno: 1, input: "- var title = 'yay'\nh1.title #{title}\np Just an example", filename: "testing/test.js" };
  var rethrow = jade.rethrow;
  try {
    var attrs = jade.attrs, escape = jade.escape;
    var buf = [];
    with (locals || {}) {
      var interp;
      __.lineno = 1;
       var title = 'yay'
      __.lineno = 2;
      buf.push('<h1');
      buf.push(attrs({ "class": ('title') }));
      buf.push('>');
      buf.push('' + escape((interp = title) == null ? '' : interp) + '');
      buf.push('</h1>');
      __.lineno = 3;
      buf.push('<p>');
      buf.push('Just an example');
      buf.push('</p>');
    }
    return buf.join("");
  } catch (err) {
    rethrow(err, __.input, __.filename, __.lineno);
  }
}

When the compileDebug option is explicitly false, this instrumentation is stripped, which is very helpful for light-weight client-side templates. Combining Jade's options with the ./runtime.js file in this repo allows you to toString() compiled templates and avoid running the entire Jade library on the client, increasing performance, and decreasing the amount of JavaScript required.

function anonymous(locals) {
  var attrs = jade.attrs, escape = jade.escape;
  var buf = [];
  with (locals || {}) {
    var interp;
    var title = 'yay'
    buf.push('<h1');
    buf.push(attrs({ "class": ('title') }));
    buf.push('>');
    buf.push('' + escape((interp = title) == null ? '' : interp) + '');
    buf.push('</h1>');
    buf.push('<p>');
    buf.push('Just an example');
    buf.push('</p>');
  }
  return buf.join("");
}

## Example Makefile

Below is an example Makefile used to compile pages/*.jade into pages/*.html files by simply executing make.

Note: If you try to run this snippet and make throws a missing separator error, you should make sure all indented lines use a tab for indentation instead of spaces. (For whatever reason, GitHub renders this code snippet with 4-space indentation although the actual README file uses tabs in this snippet.)

JADE = $(shell find . -wholename './pages/*.jade')
HTML = $(JADE:.jade=.html)

all: $(HTML)

%.html: %.jade
	jade < $< --path $< > $@

clean:
	rm -f $(HTML)

.PHONY: clean

this can be combined with the watch(1) command to produce a watcher-like behaviour:

$ watch make

or you use the watch option below:

## jade(1)

Usage: jade [options] [dir|file ...]

Options:

  -h, --help         output usage information
  -V, --version      output the version number
  -O, --obj <str>    javascript options object
  -o, --out <dir>    output the compiled html to <dir>
  -p, --path <path>  filename used to resolve includes
  -P, --pretty       compile pretty html output
  -c, --client       compile function for client-side runtime.js
  -D, --no-debug     compile without debugging (smaller functions)
  -w, --watch        watch files for changes and automatically re-render

Examples:

  # translate jade the templates dir
  $ jade templates

  # create {foo,bar}.html
  $ jade {foo,bar}.jade

  # jade over stdio
  $ jade < my.jade > my.html

  # jade over stdio
  $ echo "h1 Jade!" | jade

  # foo, bar dirs rendering to /tmp
  $ jade foo bar --out /tmp 

## Tutorials

• cssdeck interactive Jade syntax tutorial
• cssdeck interactive Jade logic tutorial
• in Japanese

## License

(The MIT License)

Copyright (c) 2009-2010 TJ Holowaychuk <tj@vision-media.ca>

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.