Node.js is a common and powerful server environment for JavaScript, and is handy to be able to work with for just about any Raspberry Pi project — it’s also one of those libraries that often requires multiple Google searches to remember how to get it installed, so I’ve consolidated my steps down to a single page.  Hopefully, you’ll only need one search next time!  (and hopefully I’ll remember that I wrote this, so I won’t need any!)

• Install Node.js – you might have a node installation on your Pi already, but chances are it’s not the one you want.  Instead, grab a fresh one:
  • curl -sL https://deb.nodesource.com/setup_9.x | sudo bash -
  • sudo apt-get install nodejs​
  • Verify this worked with node -v and npm -v (as of this writing, I get 9.4.0 and 5.6.0, respectively)
• Install the Yarn dependency manager, which we’ll use to run our app:
  • curl -sS https://dl.yarnpkg.com/debian/pubkey.gpg | sudo apt-key add -
  • echo "deb https://dl.yarnpkg.com/debian/ stable main" | sudo tee /etc/apt/sources.list.d/yarn.list
  • sudo apt-get update && sudo apt-get install yarn
  • Run yarn -v to verify (Version 1.3.2 as of today)
• Install a few handy packages using apt-get – you might not need these, but I find them necessary for many of my projects
  • sudo apt-get update
• • sudo apt-get install build-essential libavahi-compat-libdnssd-dev git

That’s it – easy, when you have everything in place!