Example Machfile (with issues) for extracting npm auth token

Machfile.edn

{
 ;; Perform initialization steps.
 mach/init (do
             (require 'fs)
             (require '[lumo.util]))

 ;; Initialize data for later use.
 mach/props [;; Read the auth token from a local .npmrc file.
             npm-token (let [file-name (str js/process.env.HOME  "/.npmrc")
                             ;; TODO this is (lumo.util/file?); prefer to use that
                             ;; instead. Right now it is not available in spite of
                             ;; that namespace being required.
                             is-file? (fn [path]
                                        (try
                                          (.isFile (fs/lstatSync path))
                                          (catch :default _
                                            false)))
                             ;; TODO Figure out why this doesn't work.
                             ;; (lumo.util/file? file-name)
                             npmrc-contents (if (is-file? file-name)
                                              (lumo.io/slurp file-name)
                                              :not-found)
                             ;; TODO figure out why using regex reader literal b0rks
                             ;;token-pattern #"_authToken=(.+)"
                             token-pattern (js/RegExp. "_authToken=(.+)")
                             token (second (re-find token-pattern npmrc-contents))]
                         token)]

 check-npm-token (if (string? npm-token)
                   (println "npm-token:" npm-token)
                   (println "Please run 'npm login' to obtain an auth token"))
}

So, it seems as though I can use mach.core/file? in place of lumo.util/file?. Progress.