gistfile1.txt

const windowUtils = require("window-utils");
const NS_XUL = "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul";


exports.Menuitem = function Menuitem(options) {
  new windowUtils.WindowTracker({
    onTrack: function (window) {
      if ("chrome://browser/content/browser.xul" != window.location) return;

 

      // add the new menuitem to a menu
 
      var menuitem = window.document.createElementNS(NS_XUL, options.type);
      menuitem.setAttribute("id", options.id);
      menuitem.setAttribute("label", options.label);
      if (options.accesskey)
        menuitem.setAttribute("accesskey", options.accesskey);
      if (options.key)
        menuitem.setAttribute("key", options.key);
      if (options.image) {
        menuitem.setAttribute("class", "menuitem-iconic");
        menuitem.style.listStyleImage = "url('" + options.image + "')";
      }
 if ( options.type == "menuitem"){
 }
 
 console.log(options.type);
 console.log(options.menuid);
      if (options.menuid) {
if (options.type == "menu"){   
let ($ = function(id) window.document.getElementById(id)) {
 
$(options.menuid).insertBefore(menuitem, $(options.insertbefore));
}
   } else {
var menu =  window.document.getElementById(options.menuid);
if ( options.onCommand){
var onCmd = function() {
options.onCommand && options.onCommand();
};
menuitem.addEventListener("command", onCmd, true);
}
menu.appendChild(menuitem);
   }
      }

      // add unloader
      require("unload+").unload(function() {
        menuitem.parentNode.removeChild(menuitem);
      }, window);
    }
  });
};

And if you call .. in the main.js of the add on this is examples.
Type is type menu (menuitem,menupopup,menu)
and menuid is the ID on insert the item.

menuitem insert into menupopup and menupopup inster into menu.



var menuitem = require("menuitems").Menuitem({
  type: "menu",
  id: "clickme",
  accesskey : "S",
  menuid: "menu_ToolsPopup",
  label: "Sundio ToolsWeb",
  insertbefore: "menu_pageInfo"
});

var menuitem = require("menuitems").Menuitem({
  type: "menupopup",
  id: "menupopup1",
  menuid: "clickme",
  label: "Click Me!"
});

var menuitem = require("menuitems").Menuitem({
  type: "menuitem",
  id: "menuitem1",
  menuid: "menupopup1",
  accesskey : "t",
  label: "Find missing textResources",
  onCommand: function() {
    console.log("clicked");
tabs.activeTab.attach({
    contentScriptFile: data.url("showmetextresources.js")});
  }
});