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PostCSS Logical Properties and Values PostCSS Logo

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 */);

PostCSS Logical Properties and Values runs in all Node environments, with special instructions for:

Options

blockDirection and 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.

ignoreCustomProperties

The ignoreCustomProperties option allows you to ignore any properties containing var().
postcss-logical assumes that all custom properties are single value (e.g. --foo: 10px;) and will assign these to physical properties as fallbacks for logical properties.

This will produce broken declarations when your custom properties contain multiple values instead (e.g. --foo: 1px 2px;).

:root {
	--inset-a: 10px;
}
.foo {
	inset: var(--inset-a);
}
:root {
	--inset-b: 1px 2px 3px 4px;
}
.bar {
	inset: var(--inset-b);
}
/* becomes */
:root {
	--inset-a: 10px;
}
.foo {
	top: var(--inset-a);
	right: var(--inset-a);
	bottom: var(--inset-a);
	left: var(--inset-a);
}
:root {
	--inset-b: 1px 2px 3px 4px;
}
.bar {
	top: var(--inset-b);
	right: var(--inset-b);
	bottom: var(--inset-b);
	left: var(--inset-b);
}

With ignoreCustomProperties set to true:

:root {
	--inset-a: 10px;
}
.foo {
	inset: var(--inset-a);
}
:root {
	--inset-b: 1px 2px 3px 4px;
}
.bar {
	inset: var(--inset-b);
}
/* becomes */
:root {
	--inset-a: 10px;
}
.foo {
	inset: var(--inset-a);
}
:root {
	--inset-b: 1px 2px 3px 4px;
}
.bar {
	inset: var(--inset-b);
}

Read the original on github.com ↗