# Jade
The jade template engine for node.js
## Synopsis
jade [-h|--help] [-v|--version] [-o|--obj STR]
[-O|--out DIR] [-p|--path PATH] [-P|--pretty]
[-c|--client] [-D|--no-debug]
## 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 s
$ echo "h1 Jade!" | jade
foo, bar dirs rendering to /tmp
$ jade foo bar --out /tmp
compile client-side templates without debugging
instrumentation, making the output javascript
very light-weight. This requires runtime.js
in your projects.
$ jade --client --no-debug < my.jade
## Tags
Tags are simply nested via whitespace, closing
tags defined for you. These indents are called "blocks".
ul
li
a Foo
li
a Bar
You may have several tags in one "block":
ul
li
a Foo
a Bar
a Baz
## Self-closing Tags
Some tags are flagged as self-closing by default, such
as `meta`, `link`, and so on. To explicitly self-close
a tag simply append the `/` character:
foo/
foo(bar='baz')/
Would yield:
<foo/>
<foo bar="baz"/>
## Attributes
Tag attributes look similar to HTML, however
the values are regular JavaScript, here are
some examples:
a(href='google.com') Google
a(class='button', href='google.com') Google
As mentioned the attribute values are just JavaScript,
this means ternary operations and other JavaScript expressions
work just fine:
body(class=user.authenticated ? 'authenticated' : 'anonymous')
a(href=user.website || 'http://google.com')
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)
## Boolean attributes
Boolean attributes are mirrored by Jade, and accept
bools, aka _true_ or _false_. When no value is specified
_true_ is assumed. For example:
input(type="checkbox", checked)
// => "<input type="checkbox" checked="checked" />"
For example if the checkbox was for an agreement, perhaps `user.agreed`
was _true_ the following would also output 'checked="checked"':
input(type="checkbox", checked=user.agreed)
## Class attributes
The _class_ attribute accepts an array of classes,
this can be handy when generated from a javascript
function etc:
classes = ['foo', 'bar', 'baz']
a(class=classes)
// => "<a class="foo bar baz"></a>"
## Class literal
Classes may be defined using a ".CLASSNAME" syntax:
.button
// => "<div class="button"></div>"
Or chained:
.large.button
// => "<div class="large button"></div>"
The previous defaulted to divs, however you
may also specify the tag type:
h1.title My Title
// => "<h1 class="title">My Title</h1>"
## Id literal
Much like the class literal there's an id literal:
#user-1
// => "<div id="user-1"></div>"
Again we may specify the tag as well:
ul#menu
li: a(href='/home') Home
li: a(href='/store') Store
li: a(href='/contact') Contact
Finally all of these may be used in any combination,
the following are all valid tags:
a.button#contact(style: 'color: red') Contact
a.button(style: 'color: red')#contact Contact
a(style: 'color: red').button#contact Contact
## Block expansion
Jade supports the concept of "block expansion", in which
using a trailing ":" after a tag will inject a block:
ul
li: a Foo
li: a Bar
li: a Baz
## Text
Arbitrary text may follow tags:
p Welcome to my site
yields:
<p>Welcome to my site</p>
## Pipe text
Another form of text is "pipe" text. Pipes act
as the text margin for large bodies of text.
p
| This is a large
| body of text for
| this tag.
|
| Nothing too
| exciting.
yields:
<p>This is a large
body of text for
this tag.
Nothing too
exciting.
</p>
Using pipes we can also specify regular Jade tags
within the text:
p
| Click to visit
a(href='http://google.com') Google
| if you want.
## Text only tags
As an alternative to pipe text you may add
a trailing "." to indicate that the block
contains nothing but plain-text, no tags:
p.
This is a large
body of text for
this tag.
Nothing too
exciting.
Some tags are text-only by default, for example
_script_, _textarea_, and _style_ tags do not
contain nested HTML so Jade implies the trailing ".":
script
if (foo) {
bar();
}
style
body {
padding: 50px;
font: 14px Helvetica;
}
## Template script tags
Sometimes it's useful to define HTML in script
tags using Jade, typically for client-side templates.
To do this simply give the _script_ tag an arbitrary
_type_ attribute such as _text/x-template_:
script(type='text/template')
h1 Look!
p Jade still works in here!
## Interpolation
Both plain-text and piped-text support interpolation,
which comes in two forms, escapes and non-escaped. The
following will output the _user.name_ in the paragraph
but HTML within it will be escaped to prevent XSS attacks:
p Welcome #{user.name}
The following syntax is identical however it will _not_ escape
HTML, and should only be used with strings that you trust:
p Welcome !{user.name}
## Inline HTML
Sometimes constructing small inline snippets of HTML
in Jade can be annoying, luckily we can add plain
HTML as well:
p Welcome <em>#{user.name}</em>
## Code
To buffer output with Jade simply use _=_ at the beginning
of a line or after a tag. This method escapes any HTML
present in the string.
p= user.description
To buffer output unescaped use the _!=_ variant, but again
be careful of XSS.
p!= user.description
The final way to mess with JavaScript code in Jade is the unbuffered
_-_, which can be used for conditionals, defining variables etc:
- var user = { description: 'foo bar baz' }
#user
- if (user.description) {
h2 Description
p.description= user.description
- }
When compiled blocks are wrapped in anonymous functions, so the
following is also valid, without braces:
- var user = { description: 'foo bar baz' }
#user
- if (user.description)
h2 Description
p.description= user.description
If you really want you could even use `.forEach()` and others:
- users.forEach(function(user){
.user
h2= user.name
p User #{user.name} is #{user.age} years old
- })
Taking this further Jade provides some syntax for conditionals,
iteration, switch statements etc. Let's look at those next!
## Assignment
Jade's first-class assignment is simple, simply use the _=_
operator and Jade will _var_ it for you. The following are equivalent:
- var user = { name: 'tobi' }
user = { name: 'tobi' }
## Conditionals
Jade's first-class conditional syntax allows for optional
parenthesis, and you may now omit the leading _-_ otherwise
it's identical, still just regular javascript:
user = { description: 'foo bar baz' }
#user
if user.description
h2 Description
p.description= user.description
Jade provides the negated version, _unless_ as well, the following
are equivalent:
- if (!(user.isAnonymous))
p You're logged in as #{user.name}
unless user.isAnonymous
p You're logged in as #{user.name}
## Iteration
JavaScript's _for_ loops don't look very declarative, so Jade
also provides its own _for_ loop construct, aliased as _each_:
for user in users
.user
h2= user.name
p user #{user.name} is #{user.age} year old
As mentioned _each_ is identical:
each user in users
.user
h2= user.name
If necessary the index is available as well:
for user, i in users
.user(class='user-#{i}')
h2= user.name
Remember, it's just JavaScript:
ul#letters
for letter in ['a', 'b', 'c']
li= letter
## Mixins
Mixins provide a way to define jade "functions" which "mix in"
their contents when called. This is useful for abstracting
out large fragments of Jade.
The simplest possible mixin which accepts no arguments might
look like this:
mixin hello
p Hello
You use a mixin by placing `+` before the name:
+hello
For something a little more dynamic, mixins can take
arguments, the mixin itself is converted to a javascript
function internally:
mixin hello(user)
p Hello #{user}
+hello('Tobi')
Yields:
<p>Hello Tobi</p>
Mixins may optionally take blocks, when a block is passed
its contents becomes the implicit `block` argument. For
example here is a mixin passed a block, and also invoked
without passing a block:
mixin article(title)
.article
.article-wrapper
h1= title
if block
block
else
p No content provided
+article('Hello world')
+article('Hello world')
p This is my
p Amazing article
yields:
<div class="article">
<div class="article-wrapper">
<h1>Hello world</h1>
<p>No content provided</p>
</div>
</div>
<div class="article">
<div class="article-wrapper">
<h1>Hello world</h1>
<p>This is my</p>
<p>Amazing article</p>
</div>
</div>
Mixins can even take attributes, just like a tag. When
attributes are passed they become the implicit `attributes`
argument. Individual attributes can be accessed just like
normal object properties:
mixin centered
.centered(class=attributes.class)
block
+centered.bold Hello world
+centered.red
p This is my
p Amazing article
yields:
<div class="centered bold">Hello world</div>
<div class="centered red">
<p>This is my</p>
<p>Amazing article</p>
</div>
If you use `attributes` directly, *all* passed attributes
get used:
mixin link
a.menu(attributes)
block
+link.highlight(href='#top') Top
+link#sec1.plain(href='#section1') Section 1
+link#sec2.plain(href='#section2') Section 2
yields:
<a href="#top" class="highlight menu">Top</a>
<a id="sec1" href="#section1" class="plain menu">Section 1</a>
<a id="sec2" href="#section2" class="plain menu">Section 2</a>
If you pass arguments, they must directly follow the mixin:
mixin list(arr)
if block
.title
block
ul(attributes)
each item in arr
li= item
+list(['foo', 'bar', 'baz'])(id='myList', class='bold')
yields:
<ul id="myList" class="bold">
<li>foo</li>
<li>bar</li>
<li>baz</li>
</ul>
