Fixing ZSH slowdown caused by NVM

Update: I have been using fnm instead of nvm for more than one year without any problems, see more in the second half of this post.

When I first started using oh-my-zsh on my MacBook, I immediately noticed was how slow it was to startup.

To find the root cause, I turned on profiling by adding in my .zshrc file zmodload zsh/zprof as the first line and zprof at the end. The results showed that nvm was the main culprit:

The best workaround I found was removing the nvm plugin inside .zshrc and replacing the default nvm stuff with the following:

export NVM_DIR="$HOME/.nvm"
[ -s "$NVM_DIR/nvm.sh" ] && . "$NVM_DIR/nvm.sh" --no-use # This loads nvm

alias node='unalias node ; unalias npm ; nvm use default ; node $@'
alias npm='unalias node ; unalias npm ; nvm use default ; npm $@'

This fixes the issue and moves the slowness to the first time you actually run node/npm/nvm. More info on this Github issue comment by @parasyte.

Alternative solution: reeplacing nvm with fnm

If you want a less “patchy” solution with less downsides, you can just entirely replace nvm with fnm, a much faster Node.js version manager written in Rust. It’s a drop-in replacement for nvm also compatible with .nvmrc and .node-version.

To stop typyng nvm by habit though, I had to create the following alias:

alias nvm='echo "(╯°□°)╯︵ɯʌu, did you mean fnm?"'