Reporting & Performance

Performance tuning

ESLint can be slow on large codebases. Use --cache to skip unchanged files, and --max-warnings to treat warnings as errors when thresholds are exceeded.

Performance optimization

Cache linting results and generate reports for visibility.

# Use cache for faster linting
eslint . --cache

# Generate JSON report
eslint . --format json > lint-report.json

# Package.json scripts
"scripts": {
  "lint": "eslint . --cache",
  "lint:report": "eslint . --format json > lint-report.json",
  "lint:html": "eslint . --format html > lint-report.html"
}

Output:

Cache and reporting configured

Clear cache regularly

ESLint cache can become stale. Clear it with rm .eslintcache or eslint . --cache --cache-location ./node_modules/.cache/eslint before major updates.

Quick check

Quick check: What does the --cache flag do?

• Caches linting results to skip unchanged files on next run.
• Stores config in memory.
• Increases memory usage.