Merge pull request #3715 from atom/do-not-edit-menu-template

Do not modify the specified menu template

atom/browser/api/lib/menu-item.coffee

@@ -26,6 +26,8 @@ class MenuItem
 
     {click, @selector, @type, @role, @label, @sublabel, @accelerator, @icon, @enabled, @visible, @checked, @submenu} = options
 
+    if @submenu? and @submenu.constructor isnt Menu
+      @submenu = Menu.buildFromTemplate @submenu
     @type = 'submenu' if not @type? and @submenu?
     throw new Error('Invalid submenu') if @type is 'submenu' and @submenu?.constructor isnt Menu
 

atom/browser/api/lib/menu.coffee

@@ -169,9 +169,8 @@ Menu.buildFromTemplate = (template) ->
   for item in positionedTemplate
     throw new TypeError('Invalid template for MenuItem') unless typeof item is 'object'
 
-    item.submenu = Menu.buildFromTemplate item.submenu if item.submenu?
     menuItem = new MenuItem(item)
-    menuItem[key] = value for key, value of item when not menuItem[key]?
+    menuItem[key] ?= value for key, value of item
     menu.append menuItem
 
   menu

docs/api/menu-item.md

@@ -26,7 +26,9 @@ Create a new `MenuItem` with the following method:
   * `visible` Boolean
   * `checked` Boolean
   * `submenu` Menu - Should be specified for `submenu` type menu item, when
-     it's specified the `type: 'submenu'` can be omitted for the menu item
+     it's specified the `type: 'submenu'` can be omitted for the menu item.
+     If the value is not a `Menu` then it will be automatically converted to one
+     using `Menu.buildFromTemplate`.
   * `id` String - Unique within a single menu. If defined then it can be used
      as a reference to this item by the position attribute.
   * `position` String - This field allows fine-grained definition of the

spec/api-menu-spec.coffee

@@ -1,6 +1,6 @@
 assert = require 'assert'
 
-{remote} = require 'electron'
+{remote, ipcRenderer} = require 'electron'
 {Menu, MenuItem} = remote.require 'electron'
 
 describe 'menu module', ->
@@ -9,6 +9,14 @@ describe 'menu module', ->
       menu = Menu.buildFromTemplate [label: 'text', extra: 'field']
       assert.equal menu.items[0].extra, 'field'
 
+    it 'does not modify the specified template', ->
+      template = ipcRenderer.sendSync 'eval', """
+        var template = [{label: 'text', submenu: [{label: 'sub'}]}];
+        require('electron').Menu.buildFromTemplate(template);
+        template;
+      """
+      assert.deepStrictEqual template, [label: 'text', submenu: [label: 'sub']]
+
     describe 'Menu.buildFromTemplate should reorder based on item position specifiers', ->
       it 'should position before existing item', ->
         menu = Menu.buildFromTemplate [