NVM lazy loading script

lazy-load-nvm.sh

#!/bin/bash

#
# NVM lazy loading script
#
# NVM takes on average half of a second to load, which is more than whole prezto takes to load.
# This can be noticed when you open a new shell.
# To avoid this, we are creating placeholder function
# for nvm, node, and all the node packages previously installed in the system
# to only load nvm when it is needed.
#
# This code is based on the scripts:
# * https://www.reddit.com/r/node/comments/4tg5jg/lazy_load_nvm_for_faster_shell_start/d5ib9fs
# * http://broken-by.me/lazy-load-nvm/
# * https://github.com/creationix/nvm/issues/781#issuecomment-236350067
#

NVM_DIR="$HOME/.nvm"

# Skip adding binaries if there is no node version installed yet
if [ -d $NVM_DIR/versions/node ]; then
  NODE_GLOBALS=(`find $NVM_DIR/versions/node -maxdepth 3 \( -type l -o -type f \) -wholename '*/bin/*' | xargs -n1 basename | sort | uniq`)
fi
NODE_GLOBALS+=("nvm")

load_nvm () {
  # Unset placeholder functions
  for cmd in "${NODE_GLOBALS[@]}"; do unset -f ${cmd} &>/dev/null; done

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

  # (Optional) Set the version of node to use from ~/.nvmrc if available
  nvm use 2> /dev/null 1>&2 || true

  # Do not reload nvm again
  export NVM_LOADED=1
}

for cmd in "${NODE_GLOBALS[@]}"; do
  # Skip defining the function if the binary is already in the PATH
  if ! which ${cmd} &>/dev/null; then
    eval "${cmd}() { unset -f ${cmd} &>/dev/null; [ -z \${NVM_LOADED+x} ] && load_nvm; ${cmd} \$@; }"
  fi
done