git clone 'https://github.com/jarzka/stylefy.git'

(ql:quickload :jarzka.stylefy)

ClojureScript library for styling UI components with ease.

Clojars Project CircleCI

API documentation


stylefy makes it possible to define UI component styles as Clojure data and attach them into components easily. When styles are defined as Clojure data, they can be easily transformed with Clojure's powerful functions (like merge) and parametrised. Styles are converted to CSS on-demand, and since the converted CSS is handled internally by the library, there is usually no need to worry about things like writing selectors, name conflicts, difficult cascading, dead CSS code etc. All in all the purpose of this library is to make writing style code easier and more maintainable.

stylefy is designed to be used in SPA applications along with Reagent. stylefy uses Garden in the background to do most of its CSS conversions.



How is this library different than Garden?

Garden is awesome, but it's “only” a Clojure to CSS generator. If you want to use Garden to style your page, you are pretty much going to write CSS code as usual, i.e. write classes and selectors to stylize things on the page. You also need to avoid CSS quirks like name conflicts and make sure you always handle CSS cascading process correctly. stylefy helps you with this; you just write your style definition in a map and attach it to your component in the render function by calling use-style. There is no need to write CSS classes or selectors, no need to worry about name conflicts etc

Yes, it is possible to easily attach styles to components with Garden too if you use inline styles. But if you use stylefy, all your style definitions are converted to unique CSS classes automatically and the corresponding class is attached to your component. This is more effective than using inline-styles, especially if the same component exists multiple times on the same page. The style is defined only once in the CSS class, not multiple times in each component instance. Also, some CSS features like pseudoclasses (:hover etc.), media queries and feature queries are not available to use as inline styles. For stylefy, this is not a problem, as it allows you to define pseudoclasses and media queries within the style map and converts everything to CSS automatically.

TLDR; stylefy it's like using inline CSS, but with full support for all CSS features that are not normally available when using CSS inline.

Any real projects using stylefy?

Yup, for example: Finnish National Access Point, Velho Design System, Solita Rooms, My personal website, and various other projects


Add Leiningen project dependency:

[stylefy "1.14.0"]



Add the following style tags on your page's head tag. It is recommended that these tags are the last style tags in the header so that it is less likely that possible other styles would override them.

The first tag is going to contain CSS definitions that are not going to change (font-face, keyframes etc.). The second will contain class definitions that are added into the DOM on-demand when components need them.

<style id="_stylefy-constant-styles_"></style>
<style id="_stylefy-styles_"></style>

Require stylefy:

(:require [stylefy.core :as stylefy])

Then, call stylefy/init once when your application starts:


Creating & using styles

Create a style as a normal Clojure map:

(def button-style {:padding "25px"
                   :background-color "#BBBBBB"
                   :border "1px solid black"})

To use it in a component, use the use-style function:

(defn- button [text]
  [:div (use-style button-style)

use-style accepts HTML attributes as the second parameter:

(defn- button [text]
  [:div (use-style button-style {:on-click #(.log js/console "Click!")
                                 :class "some-3rd-party-button-class"})

Combine & parametrise styles

Combine or parametrise styles however you like:

(def primary-button (merge generic-button {:background-color "rgb(88, 121, 193)"}))

(defn button-style [background-color]
  (merge generic-button {:background-color background-color}))

Passing styles to components

use-style is designed to be called only inside component render functions to define styles for HTML elements. If you need to pass styles to Reagent components, pass them as regular Clojure maps, and call use-style last, only for HTML elements:

(defn- button-with-custom-style [text style]
   [:button (use-style style {:on-click #(.log js/console "Click!"))
(defn- button-wrapper []
    ;; This is OK
    [button-with-custom-style "Hello" {:padding "25px"
                                       :background-color "#BBBBBB"
                                       :border "1px solid black"}]
    ;; This is NOT ok, because use-style would be called twice, second time with incorrect arguments
    [button-with-custom-style "Hello" (use-style {:padding "25px"
                                                  :background-color "#BBBBBB"
                                                  :border "1px solid black"})]])

How it works (technical details)

Calling use-style asks stylefy to save the style (if it has not been saved already) and add it into the DOM as CSS class asynchronously (soon, but not immediately). The return value is a map containing the given style properties as inline style. It is needed until the CSS class has been generated and inserted into the DOM. When the DOM is ready, the component is forced to re-render itself and use only the CSS class definition.

You might ask why does use-style work asynchronously? Consider a case when one or more components are going to be rendered and all of them are calling use-style very many times with different style maps. In this case, updating the DOM on every single call would slow the rendering process down. To keep the rendering fast, the idea is to collect as many style maps as possible during a single render event, convert all of them to CSS and add into the DOM at once.

If the style contains some specific definitions that cannot be present as inline style (some specific modes or media queries), the HTML element using the style is going to be hidden for a few milliseconds with CSS visibility set to hidden, until the converted CSS style is added into the DOM. In most cases, this should not be a problem, but if needed, the style can be added into the DOM synchronously by calling prepare-style:

[:div (use-style (prepare-style style))]

Because prepare-style causes immediate synchronous DOM update, it is not recommended to overuse it, as it can slow the rendering process. If a component needs to prepare multiple styles, it is recommend to call prepare-styles during the component-will-mount lifecycle method:

  {:component-will-mount #(stylefy/prepare-styles [style1 style2 style3])
   :render (fn []
             [:div (use-style style1)
               [:div (use-style style2)]
               [:div (use-style style3)]])})

It's good to keep in mind that most of the time either prepare-style or prepare-styles is not needed, but calling use-style is enough. Also, when caching is used, the style will be ready after its CSS has been created for the first time.

Modes (pseudo-classes & pseudo-elements)

stylefy modes are pretty much the same thing as pseudoclasses/pseudoelements in CSS and they simply create a new “class:mode” selector for your style. The reason for not using the name pseudoclass is completely self-willed; I think “mode” as a name is a little bit more informative than CSS pseudoclasses.

Here is an example of how to define a style with modes:

(def style-with-modes {:background-color "rgb(88, 121, 193)"
                       ::stylefy/mode {:hover {:background-color "rgb(98, 131, 213)"}
                                       :before {:content "'CSS generated content'"}
                                       "::-webkit-progress-bar" {:-webkit-appearance "none"}}})

In some cases the order of CSS pseudo elements is important, so writing modes in vector format is also supported:

(def style-with-modes {:background-color "white"
                       ::stylefy/mode [[:before {:content "'CSS generated content'"}]
                                       [:hover {:background-color "#ffedcf"}]
                                       [:active {:background-color "blue" :color "white"}]]})


Define a style for your component and all the elements inside of it in a single map:

(def list-container-style (merge generic-container
                                 {::stylefy/sub-styles {:list {:margin-top "1em"}
                                                        :list-item {:color "black"}}}))

(defn list-in-container []
  [:div (use-style list-container-style)
   [:ul (use-sub-style list-container-style :list)
    [:li (use-sub-style list-container-style :list-item) "List element 1"]
    [:li (use-sub-style list-container-style :list-item) "List element 2"]
    [:li (use-sub-style list-container-style :list-item) "List element 3"]]])

Another version using deeper sub-style nesting:

(def list-container-style (merge generic-container
                                   {:list {:margin-top "1em"
                                           ::stylefy/sub-styles {:item {:color "black"}}}}}))

(defn list-in-container []
  [:div (use-style list-container-style)
   [:ul (use-sub-style list-container-style :list)
    [:li (use-style (sub-style list-container-style :list :item)) "List element 1"]
    [:li (use-style (sub-style list-container-style :list :item)) "List element 2"]
    [:li (use-style (sub-style list-container-style :list :item)) "List element 3"]]])

Sub-styles are nothing special, they are supposed to contain the same contents as the main style map. If you wish, you can always omit them and use the regular use-style without any sub-styles. However, sub-styles help you to define styles that are closely related to each other in a single map, which can make style maintenance easier.

Vendor prefixes

Supported in the same way as Garden supports them.

(def button {:border "1px solid black"
             :background-color "#888888"
             :border-radius "5px"
             :color "white"
             :text-align :center
             :padding "5px"
             :width "150px"
             :height "38px"
             ::stylefy/vendors ["webkit" "moz" "o"]
             ::stylefy/auto-prefix #{:border-radius}})

You can also use globally defined vendor prefixes. These prefixes are automatically added into every style map.

(stylefy/init {:global-vendor-prefixes {::stylefy/vendors ["webkit" "moz" "o"]
                                        ::stylefy/auto-prefix #{:border-radius}}})

Media queries

Define how your style looks on various screen sizes:

(def phone-width "414px")

(def column {:padding "5px"
             :color "white"})

(def responsive-layout {:display :flex
                        :flex-direction :row
                        ::stylefy/media {{:max-width phone-width} {:flex-direction :column}}
                        ::stylefy/sub-styles {:column1 (merge column
                                                              {:background-color "#AA0000"
                                                               :flex 1})
                                              :column2 (merge column
                                                              {:background-color "#00AA00"
                                                               :flex 2})
                                              :column3 (merge column
                                                              {:background-color "#0000AA"
                                                               :flex 1})}})

(defn responsive-layout []
  [:div (use-style responsive-layout)
   [:div (use-sub-style responsive-layout :column1)
    [:p "This is column 1"]]
   [:div (use-sub-style responsive-layout :column2)
    [:p "This is column 2"]]
   [:div (use-sub-style responsive-layout :column3)
    [:p "This is column 3"]]])

You can also use modes and vendor prefixes inside media query style map.

For syntax help, see Garden's documentation.

Feature queries

Define how your style looks when certain CSS features are supported by the browser:

(def grid-style {;; Default style uses Flexbox as fallback
                 :display "flex"
                 :flex-direction "row"
                 :flex-wrap "wrap"
                 ::stylefy/media {{:max-width styles/phone-width}
                                  {:display "block"}}
                 ;; Use CSS Grid style if it is supported by the browser.
                 ;; If the browser does not support CSS Grid or feature queries at all, this
                 ;; block is simply ignored.
                 ::stylefy/supports {"display: grid"
                                     {:display "grid"
                                      :grid-template-columns "1fr 1fr 1fr"
                                      ;; Make CSS Grid responsive
                                      ::stylefy/media {{:max-width styles/phone-width}
                                                       {:grid-template-columns "1fr"}}}}})

You can use modes, media queries, and vendor prefixes inside feature query style map.

3rd party classes

Use 3rd party classes along with stylefy definitions:

(defn- bs-navbar-item [index index-atom text]
  [:li (use-style styles/clickable
          {:class (when (= @index-atom index) "active")
           :role "presentation"
           :on-click #(reset! index-atom index)})
   [:a text]])

Alternative syntax:

(defn- bs-navbar []
  (let [active-index (r/atom 0)]
    (fn []
      ;; Additional classes can also be attached in the name of the element
      [:ul.nav.nav-pills (use-style styles/boostrap-navbar-overrides)
       [bs-navbar-item 0 active-index "One"]
       [bs-navbar-item 1 active-index "Two"]
       [bs-navbar-item 2 active-index "Three"]
       [bs-navbar-item 3 active-index "Four"]])))

3rd party classes can also be attached directly into a style map. This means that the defined additional class names are always used with the style:

(def boostrap-navbar {:background-color "#DDDDDD"
                      ::stylefy/with-classes ["nav" "nav-pills"]})
(defn- bs-navbar []
  (let [active-index (r/atom 0)]
    (fn []
      [:ul (use-style boostrap-navbar)
       [bs-navbar-item 0 active-index "One"]
       [bs-navbar-item 1 active-index "Two"]
       [bs-navbar-item 2 active-index "Three"]
       [bs-navbar-item 3 active-index "Four"]])))


Call stylefy/font-face and the given font-face is added into the DOM as CSS code asynchronously.

(stylefy/font-face {:font-family "open_sans"
                    :src "url('../fonts/OpenSans-Regular-webfont.woff') format('woff')"
                    :font-weight "normal"
                    :font-style "normal"})


Call stylefy/keyframes and the given keyframes are added into the DOM as CSS code asynchronously.

(stylefy/keyframes "simple-animation"
                    {:background-color "red"}]
                    {:background-color "blue"}])

(def animated-box (merge simple-box
                         {:animation-name "simple-animation"
                          :animation-duration "3s"
                          :animation-iteration-count "infinite"}))

Custom class names

As has been told, stylefy converts style definition to unique CSS classes automatically and there is no need to worry about class names. It can, however, be useful to be able to generate custom named classes for example when working with 3rd party libraries / frameworks. For this purpose, call stylefy/class:

;; This generates a CSS class with the name "background-transition" and adds it into the DOM.
(stylefy/class "background-transition"
               {:transition "background-color 1s"})

;; Use the generated class in a component like any other class

Custom tag styles

As has been told, stylefy converts style definition to unique CSS classes automatically and there is no need to worry about writing selectors for HTML tags. However, custom tag styles can be useful for setting styles on base elements, like html or body. For this purpose, call stylefy/tag:

;; This generates a CSS tag selector and style for "body" element
(def body-style
  {:background-color :lightyellow
   :padding          :5px})

(stylefy/tag "body" body-style)

Style caching

stylefy supports style caching with HTML5 local storage. The converted CSS code is added into local storage and loaded from there when the page is reloaded.

As from version 1.7.0, caching with local storage is turned on by default. You can turn it off in the initialisation function:

  (stylefy/init {:use-caching? false})

By default, the cache is cleared in seven days. You can also clear it manually by calling:

(require '[stylefy.cache :as stylefy-cache])

Cache options

Cache options support automatic cache clearing when a certain amount of time is passed.

(stylefy/init {:use-caching? true
               :cache-options {:expires (* 1 60 60 24 7)}}) ; Cache is cleared after 7 days

Garden units and colors

You can use Garden's Unit and Color helpers with stylefy. You can also use Garden's defcssfn macro to create custom CSS functions (notice that defcssfn is a macro and needs garden.core dependency declaration).

Debugging and testing

If you want to test your user interface by examining CSS class names, stylefy's automatically generated class names can become a hassle. To make testing and debugging easier, you can use your own prefix in stylefy's automatically generated class names:

(def my-style {:color "red"
               ::stylefy/class-prefix "debugthis"}

Notice that you need to turn custom prefixes on separately on the init function:

(stylefy/init {:use-custom-class-prefix? true})

Advanced features

Multi-instance support

Running multiple apps using stylefy on the same web page is currently possible if every app is built separately (every app contains its own JS file). Every instance can use its own style tag, so use your app name as a suffix in the style tag id.

<style id="_stylefy-constant-styles_myapp"></style>
<style id="_stylefy-styles_myapp"></style>

Then init stylefy with multi-instance support. Instance-id is a unique string (for example app name). Base-node is an optional base node for style tags (handy if you use web components).

(stylefy/init {:multi-instance {:base-node (dommy/sel1 "#myapp")
                                :instance-id "myapp"}})

Manual mode

Manual mode can be used to style child elements with manually written CSS selectors using Garden syntax. It should be used only for corner cases in which complex CSS selectors are needed, or when you want to style some 3rd party child components that do not take style props as parameters. The selector and the style written in manual mode will be scoped inside the element in which you use the style map with use-style. To avoid confusion, stylefy's special keywords do not work in manual mode. For the most part, it is recommended to use sub-styles for styling child elements.

An example of such corner case is a situation in which we want to change the style of some child element when the parent element is being hovered:

(def mobile-media-query {:max-width "550px"})

(def hoverbox-style
  {:width "500px"1
   :height "200px"
   :padding "33px"
   :margin-bottom "10px"
   :background-color "#55AA55"
   ::stylefy/sub-styles {:innerbox {:width "100%"
                                    :height "100%"
                                    :background-color "#444444"}}
   ;; Change the background color of the child element when the parent element is being hovered.
   ;; This is a corner case that stylefy cannot handle directly, so we use manual mode to resolve it.
   ::stylefy/manual [[:&:hover [:.innerbox
                                ;; Brighten by default
                                {:background-color "#999999"}]]
                     (at-media mobile-media-query [:&:hover [:.innerbox
                                                             ;; Darker on mobile
                                                             {:background-color "#666666"}]])]
   ::stylefy/media {mobile-media-query
                    {:width "100%"}}})

(defn hoverbox []
  [:div (use-style hoverbox-style)
   [:div.innerbox (use-sub-style hoverbox-style :innerbox)]])

For syntax help, see Garden's documentation.

More examples

More examples available here: https://github.com/Jarzka/stylefy/tree/master/examples/src/stylefy/examples


Here: https://github.com/Jarzka/stylefy/releases

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