rtl-css-js

RTL conversion for CSS in JS objects

The problem

For some locales, it's necessary to change padding-left to padding-right when your text direction is right to left. There are tools like this for CSS (cssjanus for example) which manipulate strings of CSS to do this, but none for CSS in JS where your CSS is represented by an object.

This solution

This is a function which accepts a CSS in JS object and can convert padding-left to padding-right as well as all other properties where it makes sense to do that (at least, that's what it's going to be when it's done... This is a work in progress).

Installation

This module is distributed via npm which is bundled with node and should be installed as one of your project's dependencies:

npm install --save rtl-css-js

Usage

This module is exposed via CommonJS as well as UMD with the global as rtlCSSJS

CommonJS:

const rtlCSSJS = require('rtl-css-js')
const styles = rtlCSSJS({paddingLeft: 23})
console.log(styles) // logs {paddingRight: 23}

You can also just include a script tag in your browser and use the rtlCSSJS variable:

<script src="https://unpkg.com/rtl-css-js"></script>
<script>
const styles = rtlCSSJS({paddingRight: 23})
console.log(styles) // logs {paddingLeft: 23}
</script>

You can also control which rules you don't want to flip by adding a /* @noflip */ CSS comment to your rule

const rtlCSSJS = require('rtl-css-js')
const styles = rtlCSSJS({paddingLeft: '20px /* @noflip */'})
console.log(styles) // logs {paddingLeft: '20px /* @noflip */' }

core

rtl-css-js also exposes its internal helpers and utilities so you can deal with certain scenarios yourself. To use these you can use the rtlCSSJSCore global with the UMD build, require('rtl-css-js/core'), or use import {propertyValueConverters, arrayToObject} from 'rtl-css-js/core.esm'.

You can import anything that's exported from src/core. Please see the code comments for documentation on how to use these.

Caveats

`background`

Right now background and backgroundImage just replace all instances of ltr with rtl and right with left. This is so you can have a different image for your LTR and RTL, and in order to flip linear gradients. Note that this is case sensitive! Must be lower case. Note also that it will not change bright to bleft. It's a little smarter than that. But this is definitely something to consider with your URLs.

Inspiration

CSSJanus was a major inspiration.

Ecosystem

react-with-styles-interface-aphrodite: An interface to use react-with-styles with Aphrodite
fela-plugin-rtl: A plugin for fela that uses rtl-css-js to convert a style object to its right-to-left counterpart
bidi-css-js: A library for authoring flow-relative css, which uses rtl-css-js's core.