def node_preinstall_bin_path
    return @node_preinstall_bin_path if defined?(@node_preinstall_bin_path)

    legacy_path = "#{Dir.pwd}/#{NODE_BP_PATH}"
    path        = run("which node").strip
    if path && $?.success?
      @node_preinstall_bin_path = path
    elsif run("#{legacy_path}/node -v") && $?.success?
      @node_preinstall_bin_path = legacy_path
    else
      @node_preinstall_bin_path = false
    end
  end
checks if node.js is installed via the official heroku-buildpack-nodejs using multibuildpack
@return String if it's detected and false if it isn't