First, install Homebrew.
/usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"Install Node.js and npm with Homebrew
Then run brew update to make sure Homebrew is up to date.
brew update
As a safe measure you should run brew doctor to make sure your system is ready to brew. Run the command below and follow any recommendations from brew doctor.
brew doctor
Next, add Homebrew’s location to your $PATH in your .bash_profile or .zshrc file.
export PATH="/usr/local/bin:$PATH"
Next, install Node (npm will be installed with Node):
brew install node
To test out your Node and npm install, try installing Grunt (you might be asked to run with sudo):
npm install -g grunt-cli