lazynvm.sh

# lazyload nvm
# all props goes to http://broken-by.me/lazy-load-nvm/
# grabbed from reddit @ https://www.reddit.com/r/node/comments/4tg5jg/lazy_load_nvm_for_faster_shell_start/

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 $@
}

This does not work incase a script is run directly ./script.js.
script.js looks like:

#!/usr/bin/env node
# everything else

because env tries to find node within current paths which is not updated by the nvm due to lazy load.

solution that I found works is to create individual shell script for each of the command in the path which would trigger lazynvm(). nvm will then initialize node path at the beginning of the $PATH so that the next node call will run the node from the right path.

# lazynvm.sh
[ -s "$NVM_DIR/nvm.sh" ] && . "$NVM_DIR/nvm.sh"

# node.sh
. $(dirname "$0")/lazynvm
node $@

and then add both to $PATH in your .zshrc:

export PATH="~/lazy-load:$PATH"  # assuming both files are inside ~/lazy-load dir