What is the difference between "npm update -g", "npm upgrade -g", "npm install -g npm", and "n stable"?

Question

My npm seems out of date, so it seems I could use four different ways to update it:

sudo npm update -g          # => npm 3.8.6 sudo npm upgrade -g         # => npm 3.8.7 sudo npm install -g npm sudo npm cache clean -f && sudo npm install -g n && sudo n stable 

Some of the methods above installed npm 3.8.6, some installed 3.8.7, and the last one by n installed 3.8.3.

What are the differences between these methods and is there a standard way / official way to do it?

(The 3.8.6 and 3.8.7 difference was on my MacBook 12 inch Retina with Mac OS X v10.11 (El Capitan). It wasn't so on my MacBook Pro with Mac OS X v10.9 (Mavericks).)

Answer 1

What those commands do:

1. sudo npm update -g - this command updates all installed global packages to the the latest versions.
2. sudo npm upgrade -g - it's an alias for update command.
3. sudo npm install -g npm - installs the latest available version of npm package.
4. sudo npm cache clean -f && sudo npm install -g n && sudo n stable - cleans the npm cache, installs n (node version manager) and the latest available node.js and npm.

So, if you need update npm to the latest version only, use sudo npm install -g npm, if you want to update and node and npm, use sudo npm cache clean -f && sudo npm install -g n && sudo n stable.