update node two versions mac code example

Example: update node two versions mac

// After installation/upgrading node via brew I ran into this issue exactly: the node command worked but not the npm command.
// I used these commands to fix it.
// From: https://stackoverflow.com/questions/5056115/how-to-install-latest-version-of-node-using-brew

brew uninstall node
brew update
brew upgrade
brew cleanup
brew install node
sudo chown -R $(whoami) /usr/local
brew link --overwrite node
brew postinstall node