Change node version automatically with nvm and zsh

I have been a zsh user for a while now, for those who do not know zsh, it is a unix shell and command language based on bash with improvements. Recently, I found myself with a very slow terminal. It took a good 3 to 5 seconds to launch a new terminal session in any directory, which got increasingly annoying. The major culprit was a bash script I nicked of stackoverflow 😅 (you know you do it too) to switch node versions automatically. I decided to remove that piece of code, write my own (hopefully a simpler and improved version).

Let’s modify the zsh profile

open ~/.zshrc

To begin, open your zshrc file located here ~/.zshrc (this is platform dependent), in your favourite editor. We will be tapping into zsh hook functions to make this work, specifically chpwd, which is executed whenever the current working directory is changed.

chpwd_functions=(change_nvm_version)

Let’s define the change_node_version function. We first check if the file exits with the -f flag, it also checks that ./.nvmrc is nothing but a file. We cat the file and save the content in $version. Lastly, switch the node version with nvm (nvm use $version). I will assume you have nvm installed, otherwise check here for the installation.

function change_node_version {
	nvmrc="./.nvmrc"
	if [ -f "$nvmrc" ]; then
		version="$(cat "$nvmrc")"
		nvm use $version
	fi
}

chpwd_functions=(change_node_version)

The last step is to source your zshrc profile and voila

source ~/.zshrc 

This solution works for my needs and my terminal is faster again 🚀, feel free to suggest improvements. Until next time, stay curious !