stack error eacces permission denied mkdir '/node_modules/fsevents/build' code example
Example: Error: EACCES: permission denied, mkdir '/Users/f5238390/Sites/pyramid-ui/node_modules/node-sass/build
sudo chown -R root:YOUR_USERNAME /usr/local/lib/node_modules/
sudo chmod -R 775 /usr/local/lib/node_modules/