PostCSS Logical Properties and Values

npm install postcss-logical --save-dev

PostCSS Logical Properties and Values lets you use logical, rather than physical, direction and dimension mappings in CSS, following the CSS Logical Properties and Values specification.

.element {
    block-size: 100px;
    max-inline-size: 400px;
    inline-size: 200px;
    padding-block: 10px 20px;
    margin-inline: auto;
    border-block-width: 2px;
    border-block-style: solid;
}

/* becomes */

.element {
    height: 100px;
    max-width: 400px;
    width: 200px;
    padding-top: 10px;
    padding-bottom: 20px;
    margin-left: auto;
    margin-right: auto;
    border-top-width: 2px;
    border-bottom-width: 2px;
    border-top-style: solid;
    border-bottom-style: solid;
}

Usage

Add PostCSS Logical Properties and Values to your project:

npm install postcss postcss-logical --save-dev

Use it as a PostCSS plugin:

const postcss = require('postcss');
const postcssLogical = require('postcss-logical');

postcss([
    postcssLogical(/* pluginOptions */)
]).process(YOUR_CSS /*, processOptions */);

Options

blockDirection & inlineDirection

The blockDirection and inlineDirection options allow you to specify the direction of the block and inline axes. The default values are top-to-bottom and left-to-right respectively, which would match any latin language.

You should tweak these values so that they are specific to your language and writing mode.

postcssLogical({
    blockDirection: 'right-to-left',
    inlineDirection: 'top-to-bottom'
})

.element {
    block-size: 100px;
    max-inline-size: 400px;
    inline-size: 200px;
    padding-block: 10px 20px;
    margin-inline: auto;
    border-block-width: 2px;
    border-block-style: solid;
}

/* becomes */

.element {
    width: 100px;
    max-height: 400px;
    height: 200px;
    padding-right: 10px;
    padding-left: 20px;
    margin-top: auto;
    margin-bottom: auto;
    border-right-width: 2px;
    border-left-width: 2px;
    border-right-style: solid;
    border-left-style: solid;
}

Each direction must be one of the following:

• top-to-bottom
• bottom-to-top
• left-to-right
• right-to-left

You can't mix two vertical directions or two horizontal directions so for example top-to-bottom and right-to-left are valid, but top-to-bottom and bottom-to-top are not.

Please do note that text-align won't be transformed if inlineDirection becomes vertical.