Allow modification of menu keybindings (#923)

doc/NERDTree.txt

@@ -605,6 +605,22 @@ menu item to execute executable files.
 
 Related tags: |NERDTree-m| |NERDTreeApi|
 
+------------------------------------------------------------------------------
+                                                              *NERDTreeMenu-j*
+Default key: j
+Map option: NERDTreeMenuDown
+Applies to: The NERD tree menu.
+
+Moves the cursor down.
+
+------------------------------------------------------------------------------
+                                                              *NERDTreeMenu-k*
+Default key: k
+Map option: NERDTreeMenuUp
+Applies to: The NERD tree menu.
+
+Moves the cursor up.
+
 ==============================================================================
 3. Customisation                                             *NERDTreeOptions*
 

lib/nerdtree/menu_controller.vim

@@ -49,7 +49,7 @@ endfunction
 
 "FUNCTION: MenuController._echoPrompt() {{{1
 function! s:MenuController._echoPrompt()
-    echo "NERDTree Menu. Use j/k/enter and the shortcuts indicated"
+    echo "NERDTree Menu. Use " . g:NERDTreeMenuDown . "/" . g:NERDTreeMenuUp . "/enter and the shortcuts indicated"
     echo "=========================================================="
 
     for i in range(0, len(self.menuItems)-1)
@@ -71,9 +71,9 @@ endfunction
 "change the selection (if appropriate) and return 1 if the user has made
 "their choice, 0 otherwise
 function! s:MenuController._handleKeypress(key)
-    if a:key == 'j'
+    if a:key == g:NERDTreeMenuDown
         call self._cursorDown()
-    elseif a:key == 'k'
+    elseif a:key == g:NERDTreeMenuUp
         call self._cursorUp()
     elseif a:key == nr2char(27) "escape
         let self.selection = -1

plugin/NERD_tree.vim

@@ -148,6 +148,8 @@ call s:initVariable("g:NERDTreeMapToggleZoom", "A")
 call s:initVariable("g:NERDTreeMapUpdir", "u")
 call s:initVariable("g:NERDTreeMapUpdirKeepOpen", "U")
 call s:initVariable("g:NERDTreeMapCWD", "CD")
+call s:initVariable("g:NERDTreeMenuDown", "j")
+call s:initVariable("g:NERDTreeMenuUp", "k")
 
 "SECTION: Load class files{{{2
 call nerdtree#loadClassFiles()