For a long time, my ZSH shell windows/tabs have had very slow startup times, sometimes taking 5-10 seconds before .zshrc fully loads and the input cursor appears. This slows down my daily development cycles.

It turns out that loading NVM was the main culprit. Using this Medium post and this gist as motivation, I have added this snippet to my .zshrc file in order to lazy load nvm, npm, node, and npx (copied from the gist, credit goes to that author). I have immediately observed major speed improvements in my shell speed load times.

lazynvm() {
  unset -f nvm node npm npx
  export NVM_DIR=~/.nvm
  [ -s "$NVM_DIR/nvm.sh" ] && . "$NVM_DIR/nvm.sh" # This loads nvm
  if [ -f "$NVM_DIR/bash_completion" ]; then
    [ -s "$NVM_DIR/bash_completion" ] && \. "$NVM_DIR/bash_completion" # This loads nvm bash_completion
  fi
}

nvm() {
  lazynvm 
  nvm $@
}
 
node() {
  lazynvm
  node $@
}
 
npm() {
  lazynvm
  npm $@
}

npx() {
  lazynvm
  npx $@
}