Emacs icons not appearing as expected

Question

I am having some issue implementing a custom eshell prompt found here but I am having issue with icons. For some reason, I have not been able to get any of the icons using the unicode provided, most of them are blank. The faicon folder is showing a | character instead of the folder-o icon which is what the unicode is for. Is there a package I need to enable these icons?

(require 'dash)
(require 's)
(require 'cl)
(require 'magit)

(setq default-process-coding-system '(utf-8-unix . utf-8-unix))

(defmacro with-face (STR &rest PROPS)
  "Return STR propertized with PROPS."
  `(propertize ,STR 'face (list ,@PROPS)))

(defmacro esh-section (NAME ICON FORM &rest PROPS)
  "Build eshell section NAME with ICON prepended to evaled FORM with PROPS."
  `(setq ,NAME
         (lambda () (when ,FORM
                 (-> ,ICON
                    (concat esh-section-delim ,FORM)
                    (with-face ,@PROPS))))))

(defun esh-acc (acc x)
  "Accumulator for evaluating and concatenating esh-sections."
  (--if-let (funcall x)
      (if (s-blank? acc)
          it
        (concat acc esh-sep it))
    acc))

(defun esh-prompt-func ()
  "Build `eshell-prompt-function'"
  (concat esh-header
          (-reduce-from 'esh-acc "" eshell-funcs)
          "\n"
          eshell-prompt-string))

(esh-section esh-dir
             "\xf07c"  ;  (faicon folder)
             (abbreviate-file-name (eshell/pwd))
             '(:foreground "gold" :bold ultra-bold :underline t))

(esh-section esh-git
             "\xe907"  ;  (git icon)
             (magit-get-current-branch)
             '(:foreground "pink"))

(esh-section esh-clock
             "\xf017"  ;  (clock icon)
             (format-time-string "%H:%M" (current-time))
             '(:foreground "forest green"))

;; Below I implement a "prompt number" section
(setq esh-prompt-num 0)

(add-hook 'eshell-exit-hook (lambda () (setq esh-prompt-num 0)))

(advice-add 'eshell-send-input :before
            (lambda (&rest args) (setq esh-prompt-num (incf esh-prompt-num))))

(esh-section esh-num
             "\xf0c9"  ;  (list icon)
             (number-to-string esh-prompt-num)
             '(:foreground "brown"))

;; Separator between esh-sections
(setq esh-sep "  ")  ; or " | "

;; Separator between an esh-section icon and form
(setq esh-section-delim " ")

;; Eshell prompt header
(setq esh-header "\n ")  ; or "\n┌─"

;; Eshell prompt regexp and string. Unless you are varying the prompt by eg.
;; your login, these can be the same.
(setq eshell-prompt-regexp " ")   ; or "└─> "
(setq eshell-prompt-string " ")   ; or "└─> "

;; Choose which eshell-funcs to enable
(setq eshell-funcs (list esh-dir esh-git esh-clock esh-num))

;; Enable the new eshell prompt
(setq eshell-prompt-function 'esh-prompt-func)

Answer 1

I found out there was an issue with my fonts as I could not reference the icons using the unicode directly until after I installed the all-the-icons package. I then ran M-x all-the-icons-install-fonts Per the documentation, I added that package and edited my file to include the following

(require 'all-the-icons)
...
;; Use 'prepend for the NS and Mac ports or Emacs will crash.
(set-fontset-font t 'unicode (font-spec :family "FontAwesome") nil 'prepend)
(set-fontset-font t 'unicode (font-spec :family "all-the-icons") nil 'prepend)
...
;;Usage of icons should be like so
(esh-section esh-dir
             (all-the-icons-faicon "folder-open")  ;  (faicon folder)
             (abbreviate-file-name (eshell/pwd))
             '(:foreground "gold"))

(esh-section esh-git
             (all-the-icons-alltheicon "git")  ;  (git icon)
             (magit-get-current-branch)
             '(:foreground "pink"))

;; After installing and requiring the packages, I was able to use the ;;unicode for the icons as expected, although some were no longer available ;;in the version used in all-the-icons Font Awesome ver 4.

(esh-section esh-clock
             "\xf017"  ;  (clock icon)
             (format-time-string "%H:%M" (current-time))
             '(:foreground "forest green"))
...

(esh-section esh-num
             "\xf0c9"  ;  (list icon)
             (number-to-string esh-prompt-num)
             '(:foreground "brown"))

After making the changes to my file I load this file in my eshell profile file. My prompt now looks as I expected

My gist is here if you would like to check it out. I am running macOS Big Sur