Built-in Functions

Color Functions

red(color[, value])

Return the red component of the given color, or set the red component to the optional second value argument.

red(#c00)
// => 204

red(#000, 255)
// => #f00

green(color[, value])

Return the green component of the given color, or set the green component to the optional second value argument.

green(#0c0)
// => 204

green(#000, 255)
// => #0f0

blue(color[, value])

Return the blue component of the given color, or set the blue component to the optional second value argument.

blue(#00c)
// => 204

blue(#000, 255)
// => #00f

alpha(color[, value])

Return the alpha component of the given color, or set the alpha component to the optional second value argument.

alpha(#fff)
// => 1

alpha(rgba(0,0,0,0.3))
// => 0.3

alpha(#fff, 0.5)
// => rgba(255,255,255,0.5)

dark(color)

Check if color is dark:

dark(black)
// => true

dark(#005716)
// => true

dark(white)
// => false

light(color)

Check if color is light:

light(black)
// => false

light(white)
// => true

light(#00FF40)
// => true

hue(color[, value])

Return the hue of the given color, or set the hue component to the optional second value argument.

hue(hsl(50deg, 100%, 80%))
// => 50deg

hue(#00c, 90deg)
// => #6c0

saturation(color[, value])

Return the saturation of the given color, or set the saturation component to the optional second value argument.

saturation(hsl(50deg, 100%, 80%))
// => 100%

saturation(#00c, 50%)
// => #339

lightness(color[, value])

Return the lightness of the given color, or set the lightness component to the optional second value argument.

lightness(hsl(50deg, 100%, 80%))
// => 80%

lightness(#00c, 80%)
// => #99f

hsla(color | h,s,l,a)

Convert the given color to an HSLA node, or h,s,l,a component values.

hsla(10deg, 50%, 30%, 0.5)
// => HSLA

hsla(#ffcc00)
// => HSLA

hsl(color | h,s,l)

Convert the given color to an HSLA node, or h,s,l,a component values.

hsl(10, 50, 30)
// => HSLA

hsl(#ffcc00)
// => HSLA

rgba(color | r,g,b,a)

Return RGBA from the r,g,b,a channels, or provide a color to tweak the alpha.

rgba(255,0,0,0.5)
// => rgba(255,0,0,0.5)

rgba(255,0,0,1)
// => #ff0000

rgba(#ffcc00, 0.5)
// rgba(255,204,0,0.5)

Alternatively, Stylus supports the #rgba and #rrggbbaa notations as well:

#fc08
// => rgba(255,204,0,0.5)

#ffcc00ee
// => rgba(255,204,0,0.9)

rgb(color | r,g,b)

Return a RGBA from the r,g,b channels or cast to an RGBA node.

rgb(255,204,0)
// => #ffcc00

rgb(#fff)
// => #fff

blend(top[, bottom])

Blends the given top color over the bottom one using the normal blending. The bottom argument is optional, and defaults to #fff.

blend(rgba(#FFF, 0.5), #000)
// => #808080

blend(rgba(#FFDE00,.42), #19C261)
// => #7ace38

blend(rgba(lime, 0.5), rgba(red, 0.25))
// => rgba(128,128,0,0.625)

lighten(color, amount)

Lighten the given color by amount.

This function is unit-sensitive; it supports percentages, for example, as shown here:

lighten(#2c2c2c, 30)
// => #787878

lighten(#2c2c2c, 30%)
// => #393939

darken(color, amount)

Darken the given color by amount.

This function is unit-sensitive; it supports percentages, for example, as shown here:

darken(#D62828, 30)
// => #551010

darken(#D62828, 30%)
// => #961c1c

desaturate(color, amount)

Desaturate the given color by amount.

desaturate(#f00, 40%)
// => #c33

saturate(color, amount)

Saturate the given color by amount.

saturate(#c33, 40%)
// => #f00

complement(color)

Gives the complementary color. Equivalent to spinning hue by 180deg.

complement(#fd0cc7)
// => #0cfd42

invert(color)

Inverts the color. The red, green, and blue values are inverted. Opacity is left alone.

invert(#d62828)
// => #29d7d7

spin(color, amount)

Spins hue of the given color by amount.

spin(#ff0000, 90deg)
// => #80ff00

grayscale(color)

Gives the grayscale equivalent of the given color. Equivalent to desaturate(color, 100%).

grayscale(#fd0cc7)
// => #0cfd42

mix(color1, color2[, amount])

Mix two colors by a given amount. The amount is optional and is defaulted to 50%.

mix(#000, #fff, 30%)
// => #b2b2b2

tint(color, amount)

Mix the given color with white.

tint(#fd0cc7,66%)
// => #feaceb

shade(color, amount)

Mix the given color with black.

shade(#fd0cc7,66%)
// => #560443

luminosity(color)

Returns the relative luminance of the given color.

luminosity(white)
// => 1

luminosity(#000)
// => 0

luminosity(red)
// => 0.2126

contrast(top[, bottom])

Returns the contrast ratio object between top and bottom colors, based on script underlying “contrast ratio” tool by Lea Verou.

The second argument is optional and is defaulted to #fff.

The main key in the returned object is ratio, it also have min and max values that are different from the ratio only when the bottom color is transparent. In that case the error also contains an error margin.

contrast(#000, #fff).ratio
=> 21
contrast(#000, rgba(#FFF, 0.5))
=> { "ratio": "13.15;", "error": "-7.85", "min": "5.3", "max": "21" }

transparentify(top[, bottom, alpha])

Returns the transparent version of the given top color, as if it was blend over the given bottom color (or the closest to it, if it is possible).

The second argument is optional and is defaulted to #fff.

The third argument is optional and overrides the autodetected alpha.

transparentify(#808080)
=> rgba(0,0,0,0.5)

transparentify(#414141, #000)
=> rgba(255,255,255,0.25)

transparentify(#91974C, #F34949, 0.5)
=> rgba(47,229,79,0.5)

Path Functions

basename(path[, ext])

Returns the basename of path, (optionally) with ext extension removed.

basename('images/foo.png')
// => "foo.png"

basename('images/foo.png', '.png')
// => "foo"

dirname(path)

Returns the dirname of path.

dirname('images/foo.png')
// => "images"

extname(path)

Returns the filename extension of path including the dot.

extname('images/foo.png')
// => ".png"

pathjoin(…)

Peform a path join.

pathjoin('images', 'foo.png')
// => "images/foo.png"

path = 'images/foo.png'
ext = extname(path)
pathjoin(dirname(path), basename(path, ext) + _thumb + ext)
// => 'images/foo_thumb.png'

List / Hash Functions

push(expr, args…)

Push the given args to expr.

nums = 1 2
push(nums, 3, 4, 5)

nums
// => 1 2 3 4 5

Aliased as append().

pop(expr)

Pop a value from expr.

nums = 4 5 3 2 1
num = pop(nums)

nums
// => 4 5 3 2
num
// => 1

shift(expr)

Shift an element from expr.

nums = 4 5 3 2 1
num = shift(nums)

nums
// => 5 3 2 1
num
// => 4

unshift(expr, args…)

Unshift the given args to expr.

nums = 4 5
unshift(nums, 3, 2, 1)

nums
// => 1 2 3 4 5

Aliased as prepend().

index(list, value)

Returns the (zero-based) index of value within a list.

list = 1 2 3

index(list, 2)
// => 1

index(1px solid red, red)
// => 2

keys(pairs)

Return keys in the given pairs:

pairs = (one 1) (two 2) (three 3)
keys(pairs)
// => one two three

values(pairs)

Return values in the given pairs:

pairs = (one 1) (two 2) (three 3)
values(pairs)
// => 1 2 3

list-separator(list)

Return the separator of the given list.

list1 = a b c
list-separator(list1)
// => ' '

list2 = a, b, c
list-separator(list2)
// => ','

length([expr])

Parenthesized expressions may act as tuples, the length() function returns the length of such expressions.

length((1 2 3 4))
// => 4

length((1 2))
// => 2

length((1))
// => 1

length(())
// => 0

length(1 2 3)
// => 3

length(1)
// => 1

length()
// => 0

last(expr)

Return the last value in the given expr:

nums = 1 2 3
last(nums)
last(1 2 3)
// => 3

list = (one 1) (two 2) (three 3)
last(list)
// => (three 3)

Unit Functions

typeof(node)

Return type of node as a string.

type(12)
// => 'unit'

typeof(12)
// => 'unit'

typeof(#fff)
// => 'rgba'

type-of(#fff)
// => 'rgba'

Aliased as type-of and type.

unit(val[, type])

Return a string indicating the type of val or an empty string, or assign the given type without unit conversion.

unit(10)
// => ''

unit(15in)
// => 'in'

unit(15%, 'px')
// => 15px

unit(15%, px)
// => 15px

percentage(num)

Convert a num to a percentage.

percentage(.5)
// => 50%

percentage(4 / 100)
// => 4%

Math Functions

abs(unit)

abs(-5px)
// => 5px

abs(5px)
// => 5px

ceil(unit)

ceil(5.5in)
// => 6in

floor(unit)

floor(5.6px)
// => 5px

round(unit)

round(5.5px)
// => 6px

round(5.4px)
// => 5px

Note: All rounding functions can accept optional precision argument — you can pass the number of digits you want to save after the period:

ceil(5.52px,1)
// => 5.6px

floor(5.57px,1)
// => 5.5px

round(5.52px,1)
// => 5.5px

sin(angle)

Returns the value of sine for the given angle. If the angle is given as a degree unit, like 45deg, it is treated as a degree, otherwise it is treated as radians.

sin(30deg)
// => 0.5

sin(3*PI/4)
// => 0.707106781

cos(angle)

Returns the value of cosine for the given angle. If the angle is given as a degree unit, like 45deg, it is treated as a degree, otherwise it is treated as radians.

cos(180deg)
// => -1

tan(angle)

Returns the value of tangent for the given angle. If the angle is given as a degree unit, like 45deg, it is treated as a degree, otherwise it is treated as radians.

tan(45deg)
// => 1

tan(90deg)
// => Infinity

min(a, b)

min(1, 5)
// => 1

max(a, b)

  max(1, 5)
  // => 5

even(unit)

even(6px)
// => true

odd(unit)

odd(5mm)
// => true

sum(nums)

sum(1 2 3)
// => 6

avg(nums)

avg(1 2 3)
// => 2

range(start, stop[, step])

Returns a list of units from start to stop (included) by given step.

The step argument defaults to 1 if omitted. It cannot be 0.

range(1, 6)
// equals to `1..6`
// 1 2 3 4 5 6

range(1, 6, 2)
// 1 3 5

range(-6, -1, 2)
// -6 -4 -2

range(1px, 3px, 0.5px)
// 1px 1.5px 2px 2.5px 3px

It is most often used in for loops:

for i in range(10px, 50px, 10)
  .col-{i}
    width: i

Yields:

.col-10 {
  width: 10px;
}
.col-20 {
  width: 20px;
}
.col-30 {
  width: 30px;
}
.col-40 {
  width: 40px;
}
.col-50 {
  width: 50px;
}

base-convert(num, base, width)

Returns a Literal num converted to the provided base, padded with width zeroes.

Width defaults to 2.

base-convert(1, 10, 3)
// => 001

base-convert(14, 16, 1)
// => e

base-convert(42, 2)
// => 101010

String Functions

match(pattern, string[, flags])

Returns any matches of pattern (regular expression) in string.

match('^(height|width)?([<>=]{1,})(.*)', 'height>=1024px')
// => 'height>=1024px' 'height' '>=' '1024px'

match('^foo(?:bar)?', 'foo')
// => 'foo'

match('^foo(?:bar)?', 'foobar')
// => 'foobar'

match('^foo(?:bar)?', 'bar')
// => null

match('ain', 'The rain in SPAIN stays mainly in the plain')
// => 'ain'

match('ain', 'The rain in SPAIN stays mainly in the plain', g)
// => 'ain' 'ain' 'ain'

match('ain', 'The rain in SPAIN stays mainly in the plain', 'gi')
// => 'ain' 'AIN' 'ain' 'ain'

replace(pattern, replacement, val)

Return the string val, after replacing with all pattern matches with replacement.

replace(i, e, 'griin')
// => 'green'

replace(i, e, griin)
// => #008000

join(delim, vals…)

Join the given vals with delim.

join(' ', 1 2 3)
// => "1 2 3"

join(',', 1 2 3)
// => "1,2,3"

join(', ', foo bar baz)
// => "foo, bar, baz"

join(', ', foo, bar, baz)
// => "foo, bar, baz"

join(', ', 1 2, 3 4, 5 6)
// => "1 2, 3 4, 5 6"

split(delim, val)

The split() method splits a string or ident into a list of strings by separating the string into substrings.

split(_, bar1_bar2_bar3)
// => bar1 bar2 bar3

split(_, 'bar1_bar2_bar3')
// => 'bar1' 'bar2' 'bar3'

substr(val, start, length)

The substr() method returns the characters in a string beginning at the specified location through the specified number of characters.

substr(ident, 1, 2)
// => de

substr('string', 1, 2)
// => 'tr'

val = dredd
substr(substr(val, 1), 0, 3)
// => #f00

slice(val, start[, end])

The slice() method extracts a section of a string/list and returns a new string/list.

slice('lorem' 'ipsum' 'dolor', 1, 2)
slice('lorem' 'ipsum' 'dolor', 1, -1)
// => 'ipsum'

slice('lorem ipsum', 1, 5)
// => 'orem'
slice(rredd, 1, -1)
// => #f00

slice(1px solid black, 1)
// => solid #000

unquote(str | ident)

Unquote the given str, and return it as a Literal node.

unquote("sans-serif")
// => sans-serif

unquote(sans-serif)
// => sans-serif

unquote('1px / 2px')
// => 1px / 2px

convert(str)

Like unquote() but tries to convert the given str to a Stylus node.

unit = convert('40px')
typeof(unit)
// => 'unit'

color = convert('#fff')
typeof(color)
// => 'rgba'

foo = convert('foo')
typeof(foo)
// => 'ident'

s(fmt, …)

The s() function is similar to unquote(), in that it returns a Literal node. However, it accepts a format string similar to C’s sprintf().

Currently, the only specifier is %s.

s('bar()');
// => bar()

s('bar(%s)', 'baz');
// => bar("baz")

s('bar(%s)', baz);
// => bar(baz)

s('bar(%s)', 15px);
// => bar(15px)

s('rgba(%s, %s, %s, 0.5)', 255, 100, 50);
// => rgba(255, 100, 50, 0.5)

s('bar(%Z)', 15px);
// => bar(%Z)

s('bar(%s, %s)', 15px);
// => bar(15px, null)

Check out the % string operator for equivalent behaviour.

Utility Functions

`called-from` property

called-from property contains the list of the functions the current function was called from in reverse order (the first item is the deepest function).

foo()
  bar()

bar()
  baz()

baz()
  return called-from

foo()
// => bar foo

current-media()

current-media() function returns the string of the current block’s @media rule (or '' if there is no @media above the block).

@media only screen and (min-width: 1024px)
  current-media()
// => '@media (only screen and (min-width: (1024px)))'

+cache(keys…)

+cache is a really powerful built-in function that allows you to create your own “cachable” mixins.

A “cachable mixin” is one that would apply its contents to the given selector on the first call, but would @extend the first call’s selector at the second call with the same params.

size($width, $height = $width)
  +cache('w' + $width)
    width: $width
  +cache('h' + $height)
    height: $height

.a
  size: 10px 20px
.b
  size: 10px 2em
.c
  size: 1px 2em

Would yield to

.a,
.b {
  width: 10px;
}
.a {
  height: 20px;
}
.b,
.c {
  height: 2em;
}
.c {
  width: 1px;
}

See how the selectors are grouped together by the used property.

+prefix-classes(prefix)

Stylus comes with a block mixin prefix-classes that can be used for prefixing the classes inside any given Stylus block. For example:

+prefix-classes('foo-')
  .bar
    width: 10px

Yields:

.foo-bar {
  width: 10px;
}

lookup(name)

Allows looking up the value of a variable called name, passed as a string. Returns null if the variable is undefined.

Useful when you need to get a value of a variable with dynamically generated name:

font-size-1 = 10px
font-size-2 = 20px
font-size-3 = 30px

for i in 1..3
  .text-{i}
    font-size: lookup('font-size-' + i)

Yields:

.text-1 {
  font-size: 10px;
}
.text-2 {
  font-size: 20px;
}
.text-3 {
  font-size: 30px;
}

define(name, expr[, global])

Allows to create or overwrite a variable with a given name, passed as a string, onto current scope (or global scope if global is true).

This BIF can be useful in those cases where you need interpolation in variable names:

prefix = 'border'
border = { color: #000, length: 1px, style: solid }

for prop, val in border
  define(prefix + '-' + prop, val)

body
  border: border-length border-style border-color

yields:

body {
  border: 1px solid #000;
}

operate(op, left, right)

Perform the given op on the left and right operands:

op = '+'
operate(op, 15, 5)
// => 20

selector()

Returns the compiled current selector or & if called at root level.

.foo
  selector()
// => '.foo'

.foo
  &:hover
    selector()
// '.foo:hover'

selector-exists(selector)

Returns true if selector exists..

.foo
  color red

  a
    font-size 12px

selector-exists('.foo') // true
selector-exists('.foo a') // true
selector-exists('.foo li') // false
selector-exists('.bar') // false

This method does not take into account the current context meaning:

.foo
  color red

  a
    font-size 12px

  selector-exists('a') // false
  selector-exists(selector() + ' a') // true

opposite-position(positions)

Return the opposite of the given positions.

opposite-position(right)
// => left

opposite-position(top left)
// => bottom right

opposite-position('top' 'left')
// => bottom right

image-size(path)

Returns the width and height of the image found at path. Lookups are performed in the same manner as @import, altered by the paths setting.

width(img)
  return image-size(img)[0]

height(img)
  return image-size(img)[1]

image-size('tux.png')
// => 405px 250px

image-size('tux.png')[0] == width('tux.png')
// => true

embedurl(path[, encoding])

Returns an inline image as a url() literal, encoded with encoding.

(Available encodings: base64 (default), and utf8).

background: embedurl('logo.png')
// => background: url("data:image/png;base64,…")

background: embedurl('logo.svg', 'utf8')
// => background: url("data:image/svg+xml;charset=utf-8,…")

add-property(name, expr)

Adds property name, with the given expr to the closest block.

For example:

something()
  add-property('bar', 1 2 3)
  s('bar')

body
  foo: something()

yields:

body {
  bar: 1 2 3;
  foo: bar;
}

Next, the “magic” current-property local variable comes into play. This variable is automatically available to function bodies, and contains an expression with the current property’s name, and value.

For example, if we were to inspect this local variable using p(), we get the following:

p(current-property)
// => "foo" (foo __CALL__ bar baz)

p(current-property[0])
// => "foo"

p(current-property[1])
// => foo __CALL__ bar baz

Using current-property we can take our example a bit further, and duplicate the property with new values, and a conditional to ensure the function is only used within a property value.

something(n)
  if current-property
    add-property(current-property[0], s('-webkit-something(%s)', n))
    add-property(current-property[0], s('-moz-something(%s)', n))
    s('something(%s)', n)
  else
    error('something() must be used within a property')

body {
  foo: something(15px) bar;
}

yields:

body {
  foo: -webkit-something(15px);
  foo: -moz-something(15px);
  foo: something(15px) bar;
}

If you noticed in the example above, bar is only present for the initial call, since we returned something(15px), it remained in-place within the expression, however the others do not take the rest of the expression into account.

Our more robust solution below defines a function named replace() which clones the expression to prevent mutation, replaces the string value of an expression with another, and returns the cloned expression. We then move on to replace __CALL__ within the expressions, which represents the cyclic call to something().

replace(expr, str, val)
  expr = clone(expr)
  for e, i in expr
    if str == e
      expr[i] = val
  expr

something(n)
  if current-property
    val = current-property[1]
    webkit = replace(val, '__CALL__', s('-webkit-something(%s)', n))
    moz = replace(val, '__CALL__', s('-moz-something(%s)', n))
    add-property(current-property[0], webkit)
    add-property(current-property[0], moz)
    s('something(%s)', n)
  else
    error('something() must be used within a property')

body
  foo: something(5px) bar baz

yields:

body {
  foo: -webkit-something(5px) bar baz;
  foo: -moz-something(5px) bar baz;
  foo: something(5px) bar baz;
}

Our implementation is now fully transparent both in regards to the property it is called within, and the position of the call.

This powerful concept aids in transparent vendor support for function calls, such as gradients.

Console Functions

warn(msg)

Warn with the given error msg. Does not exit.

warn("oh noes!")

error(msg)

Exit Stylus with the given error msg.

add(a, b)
  unless a is a 'unit' and b is a 'unit'
    error('add() expects units')
  a + b

p(expr)

Inspect the given expr:

fonts = Arial, sans-serif
p('test')
p(123)
p((1 2 3))
p(fonts)
p(#fff)
p(rgba(0,0,0,0.2))

add(a, b)
  a + b

p(add)

stdout:

inspect: "test"
inspect: 123
inspect: 1 2 3
inspect: Arial, sans-serif
inspect: #fff
inspect: rgba(0,0,0,0.2)
inspect: add(a, b)

External File Functions

json(path[, options])

Convert the JSON file at path into Stylus variables or an object. Nested variable object keys are joined with a dash (-).

For example, the following sample media-queries.json file:

{
    "small": "screen and (max-width:400px)",
    "tablet": {
        "landscape": "screen and (min-width:600px) and (orientation:landscape)",
        "portrait": "screen and (min-width:600px) and (orientation:portrait)"
    }
}

May be used in the following ways:

json('media-queries.json')

@media small
// => @media screen and (max-width:400px)

@media tablet-landscape
// => @media screen and (min-width:600px) and (orientation:landscape)

vars = json('vars.json', { hash: true })
body
  width: vars.width

vars = json('vars.json', { hash: true, leave-strings: true })
typeof(vars.icon)
// => 'string'

// don't throw an error if the JSON file doesn't exist
optional = json('optional.json', { hash: true, optional: true })
typeof(optional)
// => 'null'

use(path)

You can use any JS-plugin at given path with use() function right inside your .styl files, like this:

use("plugins/add.js")

width add(10, 100)
// => width: 110

And the add.js plugin in this case looks this way:

var plugin = function(){
  return function(style){
    style.define('add', function(a, b) {
      return a.operate('+', b);
    });
  };
};
module.exports = plugin;

If you’d like to return any Stylus objects like RGBA, Ident, or Unit, you could use the provided Stylus nodes like this:

var plugin = function(){
  return function(style){
    var nodes = this.nodes;
    style.define('something', function() {
      return new nodes.Ident('foobar');
    });
  };
};
module.exports = plugin;

You can pass any options as an optional second argument, using a hash object:

use("plugins/add.js", { foo: bar })

Undefined Functions

Undefined functions are output as literals. So, for example, we may call rgba-stop(50%, #fff) within our css, and it will output as you would expect. We can use this within helpers as well.

In the example below we simply define the function stop() which returns the literal rgba-stop() call.

stop(pos, rgba)
  rgba-stop(pos, rgba)

stop(50%, orange)
// => rgba-stop(50%, #ffa500)

Built-in Functions

Color Functions

red(color[, value])

green(color[, value])

blue(color[, value])

alpha(color[, value])

dark(color)

light(color)

hue(color[, value])

saturation(color[, value])

lightness(color[, value])

hsla(color | h,s,l,a)

hsl(color | h,s,l)

rgba(color | r,g,b,a)

rgb(color | r,g,b)

blend(top[, bottom])

lighten(color, amount)

darken(color, amount)

desaturate(color, amount)

saturate(color, amount)

complement(color)

invert(color)

spin(color, amount)

grayscale(color)

mix(color1, color2[, amount])

tint(color, amount)

shade(color, amount)

luminosity(color)

contrast(top[, bottom])

transparentify(top[, bottom, alpha])

Path Functions

basename(path[, ext])

dirname(path)

extname(path)

pathjoin(…)

List / Hash Functions

push(expr, args…)

pop(expr)

shift(expr)

unshift(expr, args…)

index(list, value)

keys(pairs)

values(pairs)

list-separator(list)

length([expr])

last(expr)

Unit Functions

typeof(node)

unit(val[, type])

percentage(num)

Math Functions

abs(unit)

ceil(unit)

floor(unit)

round(unit)

sin(angle)

cos(angle)

tan(angle)

min(a, b)

max(a, b)

even(unit)

odd(unit)

sum(nums)

avg(nums)

range(start, stop[, step])

base-convert(num, base, width)

String Functions

match(pattern, string[, flags])

replace(pattern, replacement, val)

join(delim, vals…)

split(delim, val)

substr(val, start, length)

slice(val, start[, end])

unquote(str | ident)

convert(str)

s(fmt, …)

Utility Functions

called-from property

current-media()

+cache(keys…)

`called-from` property