 
          (package-json
           (if package-json-dir
-              (json-read-file (f-join package-json-dir "package.json"))
+              (json-read-file (concat
+                               (expand-file-name package-json-dir)
+                               "package.json"))
             nil))
 
          (devDependencies

              (cond ((eq style 'prettier)
                     (use-package prettier-js
                       :delight
                       :config
                       (prettier-js-mode t)
                       :bind (:map js-mode-map
                                   ("C-c f" . prettier-js))))

                    ((eq style 'eslint)
                     (use-package eslintd-fix
                       :delight
                       :config
                       (eslintd-fix-mode t)
                       :bind (:map js-mode-map
                                   ("C-c f" . eslintd-fix))))


            (babel-preset-airbnb . airbnb)
            (standard            . standard))))

    (autoload 'map-filter "map")
    (autoload 'map-contains-key "map")
    (cdr (car (map-filter
               (lambda (package _)
                 (map-contains-key devDependencies package))
