install_node.sh

#!/bin/bash
set -e

# all the available versions at: https://nodejs.org/dist
NODE_VERSION="v8.1.0"
CURRENT_VERSION=""

install_node() {
  echo "downloading and installing node $NODE_VERSION, sudo password might be required"
  curl "https://nodejs.org/dist/${NODE_VERSION}/node-${NODE_VERSION}.pkg" > "$HOME/Downloads/node-installer.pkg"
  sudo installer -store -pkg "$HOME/Downloads/node-installer.pkg" -target "/"
}

uninstall_node() {
  echo "found Node $CURRENT_VERSION but expecting $NODE_VERSION"
  echo "removing incorrect version ..."
  if brew ls --versions node > /dev/null; then
    brew uninstall --ignore-dependencies node
  else
  	echo "sudo password might be required"
    sudo rm -rf /usr/local/{bin/{node,npm},lib/node_modules/npm,lib/node,share/man/*/node.*}
  fi
}

# check if node is already installed
if type -P node > /dev/null; then
  CURRENT_VERSION="$(node -v)"
  if [ "$NODE_VERSION" == "$CURRENT_VERSION" ]; then
    echo "Node $NODE_VERSION already installed"
    exit 0 # exit script
  else
    uninstall_node
  fi
fi

install_node