Simple Node.js version manager (based on Homebrew)

.zshrc

# Simple Node.js version manager
#
# Usage example:
# $ use-node 16
#
# The strategy is to identify the Homebrew version, e.g. 'node@16', and the prepend the path to its binaries to $PATH.
# Caveat: This only supports selecting a major version, as that's the level of granularity that Homebrew provides.
use-node() {
  if [[ "$1" == "$(node --version | sed 's/v\([0-9]*\).*/\1/')" ]]; then
    return 0;
  fi

  local wanted prefix
  wanted=$([[ "$1" == "" ]] && echo "node" || echo "node@$1")
  prefix=$(brew --prefix "$wanted" 2> /dev/null)
  if [[ "$prefix" == "" ]] || [[ ! -d "$prefix" ]]; then
    echo "Node version '$1' not available" >&2
    return 1
  fi

  PATH="$(echo "$PATH" \
    | tr ':' '\n' \
    | grep -v "${prefix%@*}" \ # remove any previously added Node version paths
    | tr '\n' ':')"
  if [[ "$1" != "" ]]; then
    PATH="$prefix/bin:$PATH"
  fi
  export PATH
}

# Check for a '.node-version' file every time you enter a new directory.
# The file should contain a single line with a version.
add-zsh-hook -Uz chpwd () {
  if [[ -s ".node-version" ]] && command -v use-node > /dev/null; then
    use-node $(cat .node-version)
  fi
}