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Plumeria v7.1.2

2026-01-27

This update brings a massive performance optimization to how css.variants and css.props handles variants, along with robust conflict resolution logic.

Variant Calculation Optimization: O(n^k) -> O(n)

variants lookup implemented version is v6.0.1 or higher.

  • O(n) Additive (v7.1.0 or higher)
  • O(n^k) Product-sum (v6.3.2 or higher)
  • O(2^n) Bitwise (v6.3.1 or below)

Until v7.0.x, determining the final class name for a set of variants involved logic that could scale linearly or super-linearly depending on the number of variants and their interactions (O(n^k)). Specifically, it relied on iterative calculations to parse keys, which was not optimal for performance in tight loops (like React render cycles).

v7.1.0 introduces a fundamental shift to O(n) Constant Time lookup.

How it works

The build tool now analyzes your styles and splits them into two categories:

  1. Independent Variants: Variants that do not share any CSS properties with others.
  2. Conflicting Variants: Variants that modify the same CSS properties (e.g., color in both primary and active variants).

Constant Time Lookup table

For conflicting variants, the compiler pre-calculates a Product-Sum (Cartesian Product) table at build time. At runtime, instead of calculating logic, it simply looks up the result in a hash map using a generated key.

// Core Logic (Simplified)
// O(1) access
const className = lookupTable[props.variant] || baseClass;

This guarantees that no matter how complex your variants are, the runtime cost remains effectively zero (constant dictionary lookup).

Independent Variants Optimization

Non-conflicting variants are handled completely separately. They are treated as additive. This prevents the "combinatorial explosion" of CSS generation.

  • Before: 3 variants with 3 options each might have generated 27 (3x3x3) combined definitions.
  • After: If they are independent, we only generate 9 (3+3+3) atomic definitions and concatenate the classes.

Additive Conflict Resolution

With the new logic, conflicting styles are strictly ordered. If a Variant and Base style conflict, or multiple Variants conflict, the lookup table ensures the correct winner is applied based on the definition order, without relying on CSS cascade fragility.

  1. Remove it from the base to eliminate conflicts.
  2. The missing part is filled in with a fallback only when the variant is not specified.

Types improved

Previously, arguments were required as types rather than optionals to reduce lookup tables, this has now been fixed to allow optionals so fallbacks are fully functional.

const variants =
  <T extends Variant>(_rule: T) =>
  (_props: { [K in keyof T]?: keyof T[K] }): CSSProperties

Migration

This is a non-breaking change for valid usages. However, the combinatorial explosion has been fixed and the growth is now a constant linear growth of o(n), so there will be no performance degradation even if more patterns are defined than before.

Component Libraries

This performance optimization makes Plumeria fully viable for production component libraries.

Previously, complex variant systems with deep nesting or multiple conditional variants could introduce measurable runtime overhead. Now, with O(n) lookups and optimized conflict resolution, you can:

  • Build design systems with dozens of variants without performance concerns
  • Create reusable UI component libraries that scale to enterprise applications
  • Compose variants freely, knowing the cost is constant regardless of complexity

Whether you're building an internal design system or publishing a public component library on npm, your styling layer is never the bottleneck.

Upgrade today to experience the speed up!

Feedback Discussion and bug Issues reports are welcome on GitHub