How to delete menu item defined in a parent major from within derived mode?

Question

I'm creating custom major mode derived from js-mode which comes with it's own menu entry "Javascript" (top-level entry, between Tools & Help (sorry, not sure what the correct name for that UI element is)).

I would like to hide/remove that menu since I don't have need for it (deriving from js-mode mostly for indentation settings which I know is probably an overkill).

I found this piece of information here:

(define-key global-map [menu-bar words] nil)

so I have tried calling

(define-key global-map [menu-bar javascript] nil)

from inside define-derived-mode and my-mode-hook, but neither option worked (javascript menu bar name was guessed based on the UI label as I am not sure where can I check the actual name).

Any ideas on what I'm doing wrong with this approach? Or perhaps there is another way to hide/remove menu items?

Answer 1

Assuming your major mode is defined with something like:

(defvar my-mode-map
  (let ((map (make-sparse-keymap)))
    <my-own-bindings>
    map))

(define-derived-mode my-mode js-mode "My"
  "Major mode for My language."
  <my-own-settings>)

then you can try to put

(define-key map [menu-bar JavaScript] #'undefined)

somewhere within the <my-own-bindings>.