How do I fix permission denied errors on macOS?

Answer

For npm global packages: avoid sudo, instead fix ownership with sudo chown -R $(whoami) ~/.npm and sudo chown -R $(whoami) /usr/local/lib/node_modules. For project files: chmod -R u+rw your-project/. If using nvm, permission issues are rare since packages install in your home directory. For EACCES on .vibgrate folder: chmod -R 755 .vibgrate.