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:
// force at least one dir attribute (this can run at any time)
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');
.process(YOUR_CSS /*, processOptions, pluginOptions */); postcssDirPseudoClass
Or use it as a PostCSS plugin:
const postcss = require('postcss');
const postcssDirPseudoClass = require('postcss-dir-pseudo-class');
postcss([
postcssDirPseudoClass(/* pluginOptions */)
.process(YOUR_CSS /*, processOptions */); ])
PostCSS Dir Pseudo Class runs in all Node environments, with special instructions for:
Node | PostCSS CLI | Webpack | Create React App | Gulp | Grunt |
---|
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;
}