css-deadweigth/lib/scanSource.js

CLI tool to detect unused CSS in your project

import fs from 'fs/promises';

export async function extractUsedSelectors(sourceFilePaths) {
  const usedSelectors = new Set();

  const classRegex = /class(Name)?=["'`]([^"'`]+)["'`]/g;
  const idRegex = /id=["'`]([^"'`]+)["'`]/g;

  // Parallel read source files
  const contents = await Promise.all(sourceFilePaths.map(file => fs.readFile(file, 'utf-8')));

  for (const content of contents) {
    let match;

    while ((match = classRegex.exec(content)) !== null) {
      const classes = match[2].split(/\s+/);
      classes.forEach(cls => usedSelectors.add(`.${cls}`));
    }

    while ((match = idRegex.exec(content)) !== null) {
      usedSelectors.add(`#${match[1]}`);
    }
  }

  return usedSelectors;
}