Plumeria v4.1.3

v4.1.3

Fixed

• Removed debug console output that was accidentally included in v4.1.2 (turbopack-loader)

release note v4.1.2

Props function performance improvements

The css.props function has been significantly refactored and optimized across versions, achieving 82.7% performance improvement over the v3.1.0 implementation.

Key optimization: Set-based deduplication

The major breakthrough came from using a persistent Set instance (defined) that is cleared at the start of each call, rather than creating a new array on every invocation. This approach:

• Eliminates array allocation overhead - Reuses the same Set instance across calls
• Provides O(1) lookup performance - Set.has() is significantly faster than array operations
• Reduces memory pressure - No new objects created per function call

Implementation

const defined = new Set<string>();

function props(...rules: (false | CSSProperties | null | undefined)[]): string {
  defined.clear();
  let result = '';

  for (let i = rules.length - 1; i >= 0; i--) {
    const arg = rules[i] as Record<string, string>;
    if (!arg || typeof arg !== 'object') continue;

    let chunk = '';
    for (const key in arg) {
      if (arg[key] && !defined.has(key)) {
        defined.add(key);
        chunk += chunk ? ' ' + arg[key] : arg[key];
      }
    }

    if (chunk) result = result ? chunk + ' ' + result : chunk;
  }

  return result;
}

Benchmark results

Performance comparison (200 iterations, each processing 5 objects with 300 properties):

The Set-based implementation (v4.1.2+) is nearly 6x faster than the original v3.1.0, making it highly efficient for runtime style composition with large property sets.

View the full implementation: core/css.ts on GitHub