What is postcss-dir-pseudo-class?
The postcss-dir-pseudo-class package is a PostCSS plugin that allows you to use the :dir pseudo-class in CSS, enabling styling based on the directionality of text (e.g., left-to-right or right-to-left). This is particularly useful for creating styles that need to adapt to different language directionality, such as supporting both English (LTR) and Arabic or Hebrew (RTL) without having to write separate CSS rules for each.
What are postcss-dir-pseudo-class's main functionalities?
Directional Styling
Allows styling elements differently based on the text direction. This is useful for creating layouts and designs that adapt to both LTR and RTL languages.
/* Input CSS */
:dir(ltr) .selector { float: left; }
:dir(rtl) .selector { float: right; }
/* Output CSS */
.selector:dir(ltr) { float: left; }
.selector:dir(rtl) { float: right; }
Fallback Support
Generates fallbacks for browsers that do not support the :dir pseudo-class, using the [dir] attribute selector instead. This ensures compatibility across a wider range of browsers.
/* Input CSS */
:dir(ltr) .selector { float: left; }
:dir(rtl) .selector { float: right; }
/* Output CSS with fallback */
[dir='ltr'] .selector { float: left; }
[dir='rtl'] .selector { float: right; }
Other packages similar to postcss-dir-pseudo-class
rtlcss
RTLCSS is a framework for converting Left-To-Right (LTR) CSS to Right-To-Left (RTL). While postcss-dir-pseudo-class focuses on providing directional styling capabilities within CSS, RTLCSS specifically targets the conversion of existing LTR CSS to RTL, making it more suitable for projects that need to automate the generation of RTL stylesheets from their LTR counterparts.
postcss-rtl
Similar to RTLCSS, postcss-rtl is a PostCSS plugin designed to convert LTR CSS to RTL. It offers a different approach and syntax for defining directional styles compared to postcss-dir-pseudo-class, focusing more on the conversion aspect rather than enabling the direct use of :dir pseudo-class in stylesheets.
PostCSS Dir Pseudo Class
PostCSS Dir Pseudo Class lets you style by directionality using the :dir()
pseudo-class in CSS, following the Selectors specification.
article h3:dir(rtl) {
margin-right: 10px;
}
article h3:dir(ltr) {
margin-left: 10px;
}
/* becomes */
[dir="rtl"] article h3 {
margin-right: 10px;
}
[dir="ltr"] article h3 {
margin-left: 10px;
}
Maintaining Specificity
Using PostCSS Dir Pseudo Class will not impact selector weight, but it will
require having at least one [dir]
attribute in your HTML. If you don’t have
any [dir]
attributes, consider using the following JavaScript:
document.documentElement.dir=document.documentElement.dir||'ltr';
If you absolutely cannot add a [dir]
attribute in your HTML or even force one
via JavaScript, you can still work around this by presuming a direction in your
CSS using the dir
option, but understand that this will
sometimes increase selector weight by one element (html
).
Usage
Add PostCSS Dir Pseudo Class to your project:
npm install postcss-dir-pseudo-class --save-dev
Use PostCSS Dir Pseudo Class to process your CSS:
const postcssDirPseudoClass = require('postcss-dir-pseudo-class');
postcssDirPseudoClass.process(YOUR_CSS );
Or use it as a PostCSS plugin:
const postcss = require('postcss');
const postcssDirPseudoClass = require('postcss-dir-pseudo-class');
postcss([
postcssDirPseudoClass()
]).process(YOUR_CSS );
PostCSS Dir Pseudo Class runs in all Node environments, with special instructions for:
Options
dir
The dir
option allows you presume a direction in your CSS. By default, this
is not specified and you are required to include a direction [dir]
attribute
somewhere in your HTML, preferably on the html
element.
Here’s an example of using the dir
option to presume a left-to-right
direction:
postcssDirPseudoClass({ dir: 'ltr' });
.example:dir(ltr) {
margin-left: 10px;
}
.example:dir(rtl) {
margin-right: 10px;
}
/* becomes */
html:not([dir="rtl"]) .example {
margin-left: 10px;
}
[dir="rtl"] .example {
margin-right: 10px;
}
preserve
The preserve
option determines whether the original :dir()
rule should
remain in the CSS. By default, the original rule is not preserved.
postcssDirPseudoClass({ preserve: true });
article h3:dir(rtl) {
margin-right: 10px;
}
article h3:dir(ltr) {
margin-left: 10px;
}
/* becomes */
[dir="rtl"] article h3 {
margin-right: 10px;
}
article h3:dir(rtl) {
margin-right: 10px;
}
[dir="ltr"] article h3 {
margin-left: 10px;
}
article h3:dir(ltr) {
margin-left: 10px;
}