I'm trying to use node 8.9.1 but when trying to update using brew it says 8.9.1 is already installed
James-MacBook:~ james$ brew upgrade node
Error: node 8.9.1 already installed
But when checking the version it shows
James-MacBook:~ james$ node --version
v0.10.48
So then I tried to switch to 8.9.1
James-MacBook:~ james$ brew switch node 8.9.1
Cleaning /usr/local/Cellar/node/8.9.1
7 links created for /usr/local/Cellar/node/8.9.1
But it is still showing as 0.10.48
James-MacBook:~ james$ node --version
v0.10.48
It sounds like you have some version of node that is installed without using Homebrew.
ls -la
brew update && brew install node@8
(whichever node you want)brew unlink node@0
brew link --force node@8
Happy coding