Unused CSS Scanner 🔍

A powerful npm package to scan React Native and React files to find unused CSS classes and StyleSheet definitions.

Features

• ✅ Scans React Native StyleSheet.create() definitions
• ✅ Detects unused styles in your components
• ✅ Supports .tsx, .ts, .jsx, .js files
• ✅ Generates detailed reports with usage statistics
• ✅ CLI and programmatic API
• ✅ Customizable ignore patterns

Installation

npm install unused-css-scanner --save-dev
# or
yarn add unused-css-scanner --dev

Usage

Interactive Mode (Recommended)

unused-css-scanner
# or
unused-css-scanner scan

This will:

1. Ask you which folder to scan
2. Let you choose scan mode (all at once or one by one)
3. Show detailed reports
4. Ask permission to delete unused styles

Scan Specific Folder

unused-css-scanner src/

Scan Single File

unused-css-scanner src/HomeScreen.tsx

Show Help

unused-css-scanner help
# or
unused-css-scanner --help

Show Version

unused-css-scanner --version

Programmatic API

import UnusedCSSScanner from "unused-css-scanner";

// Create scanner instance
const scanner = new UnusedCSSScanner({
  files: ["src/HomeScreen.tsx", "src/Profile.tsx"],
  extensions: [".tsx", ".ts", ".jsx", ".js"],
  ignorePatterns: [/node_modules/, /\.test\./],
});

// Scan files and get results
const { results, report } = scanner.scan();

console.log(report);

// Access detailed results
results.forEach((result) => {
  console.log(`File: ${result.file}`);
  console.log(`Unused styles: ${result.unusedStyles.join(", ")}`);
});

Example with Your Code

Given this React Native component:

<View style={styles.sectionHeader}>
  <Text style={styles.sectionTitle}>Popular PGs</Text>
  <TouchableOpacity onPress={allPG}>
    <Text style={styles.seeAll}>See All →</Text>
  </TouchableOpacity>
</View>

And StyleSheet:

const styles = StyleSheet.create({
  container: { flex: 1 },
  header: { backgroundColor: Colors.primary },
  sectionHeader: { flexDirection: "row" },
  sectionTitle: { fontSize: FontSize.xxl },
  seeAll: { fontSize: FontSize.md },
  // ... more styles
});

Output:

📊 Unused CSS/Style Classes Report
══════════════════════════════════════════════════

📄 File: src/HomeScreen.tsx
   Defined: 15 | Used: 3 | Unused: 12
   ❌ Unused: container, header, searchSection, searchInput, ...

══════════════════════════════════════════════════
📈 Summary:
   Total Styles Defined: 15
   Total Styles Used: 3
   Total Styles Unused: 12
   Usage Rate: 20.00%

API Reference

UnusedCSSScanner

Constructor Options

interface ScanOptions {
  files: string[]; // Array of file paths to scan
  styleFiles?: string[]; // Optional: specific style files
  extensions?: string[]; // File extensions to scan (default: ['.tsx', '.ts', '.jsx', '.js'])
  ignorePatterns?: RegExp[]; // Patterns to ignore (default: [/node_modules/, /\.test\./])
}

Methods

• scanFile(filePath: string): StyleUsage | null - Scan a single file
• scanFiles(files?: string[]): StyleUsage[] - Scan multiple files
• generateReport(results: StyleUsage[]): string - Generate text report
• scan(files?: string[]): { results: StyleUsage[], report: string } - Scan and generate report

Return Types

interface StyleUsage {
  file: string; // File path
  definedStyles: string[]; // All defined style names
  usedStyles: string[]; // Used style names
  unusedStyles: string[]; // Unused style names
}

Configuration Examples

Ignore Specific Patterns

const scanner = new UnusedCSSScanner({
  files: ["src/**/*.tsx"],
  ignorePatterns: [/node_modules/, /\.test\./, /\.stories\./, /__snapshots__/],
});

Custom Extensions

const scanner = new UnusedCSSScanner({
  files: ["src/**/*"],
  extensions: [".tsx", ".jsx", ".ts", ".js", ".mjs"],
});

Integration with CI/CD

Add to your package.json:

{
  "scripts": {
    "lint:css": "unused-css-scanner src/**/*.tsx",
    "precommit": "npm run lint:css"
  }
}

The CLI exits with code 1 if unused styles are found, making it perfect for CI/CD pipelines.

Supported Patterns

The scanner detects:

• style={styles.styleName}
• style={[styles.style1, styles.style2]}
• className="styleName"
• className={styles.styleName}
• Any reference to styles.styleName

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

License

MIT

Author

Chandan Jadhav

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Made with ❤️ for cleaner React Native codebases