purgecss-cli

Remove unused CSS from your project with a fast CommonJS CLI.
Zero‑config via cosmiconfig, smart Tailwind extraction, minify, watch, reports, and friendly interactive prompts (only when --content / --css are missing).

✨ Features

• Dead‑CSS removal via PurgeCSS (battle‑tested)
• CommonJS CLI (no ESM required)
• cosmiconfig support
  Auto‑discovers config from package.json, .purgecss-clirc.*, purgecss-cli.config.*
• Interactive prompts (asks for content & css only if missing)
• Tailwind‑aware extractor (handles variants & arbitrary values)
• Minify output with CSSO (--minify)
• Watch mode (--watch)
• JSON reports (--report)
• Backups (--backup) of originals
• Safelisting (exact & regex)
• Rejected list per file (--rejected → *.rejected.txt)

🧭 Installation

# local dev dependency
npm i -D purgecss-cli

# or global for quick use
npm i -g purgecss-cli

🚀 Quick Start

# If your config already defines content/css, this just runs:
npx purgecss-cli

# Or pass globs explicitly:
npx purgecss-cli \
  -c "src/**/*.{html,js,jsx,ts,tsx,vue,svelte,md,mdx}" \
  -s "dist/**/*.css" \
  --tailwind --minify --rejected

If --content or --css are missing, the CLI will prompt for them.

📦 Configuration (cosmiconfig)

purgecss-cli loads config from any of these (first match wins):

• package.json → "purgecss-cli": { ... }
• .purgecss-clirc / .purgecss-clirc.{json,yaml,yml,js,cjs}
• purgecss-cli.config.{js,cjs,json,yaml,yml}

Example (JSON)

{
  "content": ["src/**/*.{html,js,jsx,ts,tsx,vue,svelte,md,mdx}"],
  "css": ["dist/**/*.css"],
  "tailwind": true,
  "minify": true,
  "rejected": true,
  "safelist": ["modal-open", "prose"],
  "safelistPatterns": ["^btn-", "^(enter|leave)-"],
  "out": "pruned/",
  "report": "reports/prune.json"
}

CLI flags override values from config.

🧪 Common Commands

# Initialize a sample config file in the current directory
npx purgecss-cli --init

# Basic run (no prompts if config covers it)
npx purgecss-cli

# Explicit globs + Tailwind extractor + minify
npx purgecss-cli -c "src/**/*.{html,tsx}" -s "dist/**/*.css" --tailwind --minify

# Output to a different folder (keeps filenames)
npx purgecss-cli -c "src/**/*.{html,tsx}" -s "dist/**/*.css" -o pruned/

# Keep certain classes always
npx purgecss-cli -c "src/**/*" -s "dist/**/*.css" --safelist modal-open prose

# Keep classes by regex (e.g., keep all btn-* and text-*)
npx purgecss-cli -c "src/**/*" -s "dist/**/*.css" --safelist-patterns "^btn-" "^text-"

# Inspect removed selectors (writes .rejected.txt next to outputs)
npx purgecss-cli -c "src/**/*" -s "dist/**/*.css" --rejected

# JSON report with size savings per file
npx purgecss-cli -c "src/**/*" -s "dist/**/*.css" --report reports/run.json

# Watch for changes and re-run automatically
npx purgecss-cli -c "src/**/*" -s "dist/**/*.css" --watch

# Dry run: calculate savings without writing files
npx purgecss-cli -c "src/**/*" -s "dist/**/*.css" --dry-run

🧵 Tailwind Notes

• Enable Tailwind parsing with --tailwind (or tailwind: true in config).
• The built‑in extractor handles variants like md:hover:underline and arbitrary values like w-[37%].
• Dynamic classes (e.g., className={"btn-" + size}) aren’t visible to static analysis—use safelist:
  • Exact: --safelist btn-sm btn-lg
  • Regex: --safelist-patterns "^btn-"

🔒 Safelisting Basics

• Exact classes: --safelist modal-open prose
• Regex patterns: --safelist-patterns "^toast-" "^(enter|leave)-"
• In config, you can provide arrays:

  { "safelist": ["modal-open"], "safelistPatterns": ["^btn-"] }

🗂 Output, Backups & Reports

• Overwrite in place by default.
• Output to a folder with -o pruned/.
• Back up originals (only when overwriting in place) with --backup → saves *.bak.
• Rejected selectors (--rejected) → writes filename.css.rejected.txt.
• JSON report (--report path.json) includes per‑file before/after/saved bytes and rejected counts.

👀 Watch Mode

npx purgecss-cli -c "app/**/*.{tsx,html}" -s ".next/static/css/*.css" --tailwind --watch

Watches both content & CSS globs. On change, re‑runs pruning (debounced).

🧰 CI / Scripts

Add to package.json:

{
  "scripts": {
    "prune:css": "purgecss-cli --minify --rejected --report reports/prune.json"
  }
}

Then:

npm run prune:css

Use in CI after your build step, before packaging artifacts.

🧯 Troubleshooting (CJS)

ESM‑only dependency error (e.g., chalk, cosmiconfig, ora)

• Prefer CJS‑friendly versions: chalk@4, cosmiconfig@8, ora@5.
• Or dynamically import ESM at runtime in CJS (advanced).

Classes missing after prune
Safelist dynamic/conditionally built classes via --safelist / --safelist-patterns. Check the *.rejected.txt file to see what got removed.

No files matched
Wrap globs in quotes so your shell doesn’t expand them early:

-c "src/**/*.{html,tsx}" -s "dist/**/*.css"

Tailwind JIT
Point content globs at your source files (where class names live), not just compiled HTML.

📚 Options Reference