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Release 0.6.1

· 3 min read
Naman Goel

We're excited to release StyleX v0.6.1 with some big improvements for working with CSS custom properties (aka "variables") as well as numerous bug-fixes.

Improvements for variables

We've added some new features and improvements for working with variables and themes in StyleX.

Fallback values for variables

You can now provide a fallback value for variables defined with the stylex.defineVars API. This new capability does not introduce any new API. Instead, the existing stylex.firstThatWorks API now supports variables as arguments.

import * as stylex from '@stylexjs/stylex';
import {colors} from './tokens.stylex';

const styles = stylex.create({
container: {
color: stylex.firstThatWorks(colors.primary, 'black'),

Using a list of fallbacks variables is supported.

Typed variables

StyleX introduces a brand new set of APIs for defining <syntax> types for CSS variables. This results in @property rules in the generated CSS output which can be used to animate CSS variables as well as other special use-cases.

The new stylex.types.* functions can be used when defining variables to define them with a particular type.

import * as stylex from '@stylexjs/stylex';

const typedTokens = stylex.defineVars({
bgColor: stylex.types.color<string>({
default: 'cyan',
[DARK]: 'navy',
cornerRadius: stylex.types.length<string | number>({
default: '4px',
'@media (max-width: 600px)': 0,
translucent: stylex.types.number<number>(0.5),
angle: stylex.types.angle<string>('0deg'),
shortAnimation: stylex.types.time<string>('0.5s'),

Once variables have been defined with types, they can be animated with stylex.keyframes just like any other CSS property.

import * as stylex from '@stylexjs/stylex';
import {typedTokens} from './tokens.stylex';

const rotate = stylex.keyframes({
from: { [typedTokens.angle]: '0deg' },
to: { [typedTokens.angle]: '360deg' },

const styles = stylex.create({
gradient: {
backgroundImage: `conic-gradient(from ${tokens.angle}, ...colors)`,
animationName: rotate,
animationDuration: '10s',
animationTimingFunction: 'linear',
animationIterationCount: 'infinite',

This can be used achieve some interesting effects, such as animating the angle of a conic-gradient:

This new capability is primarily about CSS types, but the new API also makes the TypeScript (or Flow) types for the variables more powerful.

As can be seen in the example, generic type arguments can be used to constrain the values the variable can take when creating themes with stylex.createTheme.

ESlint plugin

New sort-keys rule

We've added a new sort-keys rule to the StyleX ESlint plugin. This rule is a stylistic rule to enforce a consistent order for keys for your StyleX styles.

Thanks nedjulius & QingqiShi

Improvements to propLimits for valid-styles rule.

The valid-styles rule has been improved to allow more expressive "prop limits".


  • ESlint 'valid-styles' rule now allows using variables created with stylex.defineVars as keys within dynamic styles.
  • Bug-fixes to the experimental stylex.include API
  • Fixed debug className generation for stylex.createTheme
  • Units are no longer removed from 0 values
  • Compilation bug-fixes

Our Ecosystem page continues to grow with community projects. Including a Prettier plugin for sorting StyleX styles.