recss-core

Core analysis engine for ReCSS.

Install

pnpm add recss-core

Purpose

• Parse CSS and source files
• Analyze unused classes and specificity conflicts
• Provide report renderers and config utilities
• Build and apply CSS Modules migration suggestions

Migration API

The migration flow is exposed as two public functions:

• buildMigrationSuggestions(root) — scans a directory for plain CSS/SCSS files and returns migration suggestions (detected classes, suggested .module file paths).
• applyMigrationSuggestions(root, suggestions) — copies style files to .module equivalents and rewrites class references in React and Vue source files.

React className rewrite patterns

Supported: string literals, template literals, clsx/cn/classnames calls, array literals, .filter(Boolean).join(" "), .concat() chains, binary string concatenation ("a " + b), conditional/logical expressions, and wrapper function calls whose nested arguments use supported class patterns.

Vue SFC rewrite patterns

Supported: static class, object :class, array :class, mixed static + dynamic bindings, custom <style module="alias"> references, wrapper function calls around supported expressions, and template rewrites that follow useCssModule() accessors declared in <script> or <script setup>.

Limitations

This is a targeted migration helper, not a general AST transformer. Dynamic variable references and complex member expressions are left untouched. Wrapper calls are only rewritten when their nested arguments match supported class patterns, and ambiguous class names across multiple imported style modules are intentionally left unchanged.