don't reassign parameters in Menu.prototype.popup

lib/browser/api/menu.js

@@ -11,7 +11,8 @@ let groupIdIndex = 0
 
 Object.setPrototypeOf(Menu.prototype, EventEmitter.prototype)
 
-// cleaned up
+/* Instance Methods */
+
 Menu.prototype._init = function () {
   this.commandsMap = {}
   this.groupsMap = {}
@@ -45,39 +46,33 @@ Menu.prototype._init = function () {
 // create and show a popup
 Menu.prototype.popup = function (window, x, y, positioningItem) {
   let asyncPopup
+  let [newX, newY, newPosition, newWindow] = [x, y, positioningItem, window]
 
   // menu.popup(x, y, positioningItem)
-  if (window != null && (typeof window !== 'object' || window.constructor !== BrowserWindow)) {
-    // Shift.
-    positioningItem = y
-    y = x
-    x = window
-    window = null
+  if (window !== null) {
+    // shift over values
+    if (typeof window !== 'object' || window.constructor !== BrowserWindow) {
+      [newPosition, newY, newX, newWindow] = [y, x, window, null]
+    }
   }
 
   // menu.popup(window, {})
-  if (x != null && typeof x === 'object') {
-    const options = x
-    x = options.x
-    y = options.y
-    positioningItem = options.positioningItem
-    asyncPopup = options.async
+  if (x !== null && typeof x === 'object') {
+    const opts = x
+    newX = opts.x
+    newY = opts.y
+    newPosition = opts.positioningItem
+    asyncPopup = opts.async
   }
 
-  // Default to showing in focused window.
-  if (window == null) window = BrowserWindow.getFocusedWindow()
-
-  // Default to showing under mouse location.
-  if (typeof x !== 'number') x = -1
-  if (typeof y !== 'number') y = -1
-
-  // Default to not highlighting any item.
-  if (typeof positioningItem !== 'number') positioningItem = -1
-
-  // Default to synchronous for backwards compatibility.
+  // set defaults
+  if (typeof x !== 'number') newX = -1
+  if (typeof y !== 'number') newY = -1
+  if (typeof positioningItem !== 'number') newPosition = -1
+  if (window === null) newWindow = BrowserWindow.getFocusedWindow()
   if (typeof asyncPopup !== 'boolean') asyncPopup = false
 
-  this.popupAt(window, x, y, positioningItem, asyncPopup)
+  this.popupAt(newWindow, newX, newY, newPosition, asyncPopup)
 }
 
 // close an existing popup
@@ -138,6 +133,8 @@ Menu.prototype._callMenuWillShow = function () {
   })
 }
 
+/* Static Methods */
+
 // return application menu
 Menu.getApplicationMenu = () => applicationMenu
 
@@ -187,7 +184,7 @@ Menu.buildFromTemplate = function (template) {
   return menu
 }
 
-/* Helper Methods */
+/* Helper Functions */
 
 // Search between separators to find a radio menu item and return its group id
 function generateGroupId (items, pos) {
@@ -253,11 +250,11 @@ function indexToInsertByPosition (items, position) {
 }
 
 // insert a new MenuItem depending on its type
-function insertItemByType(item, pos) {
+function insertItemByType (item, pos) {
   const types = {
     'normal': () => this.insertItem(pos, item.commandId, item.label),
     'checkbox': () => this.insertCheckItem(pos, item.commandId, item.label),
-    'separator':() => this.insertSeparator(pos),
+    'separator': () => this.insertSeparator(pos),
     'submenu': () => this.insertSubMenu(pos, item.commandId, item.label, item.submenu),
     'radio': () => {
       // Grouping radio menu items