feat: add node.open.toggle_group_empty, default mapping L (#2647)

* feat: ungrouping empty directories

* add a new api to toggle empty folders

* solve comments

* solve comments

* update help

---------

Co-authored-by: juefei yan <juefeiyan@juefeis-MacBook-Air.local>
Co-authored-by: Alexander Courtis <alex@courtis.org>

doc/nvim-tree-lua.txt

@@ -181,6 +181,7 @@ Show the mappings:  `g?`
 `I`               Toggle Filter: Git Ignore  |nvim-tree-api.tree.toggle_gitignore_filter()|
 `J`               Last Sibling               |nvim-tree-api.node.navigate.sibling.last()|
 `K`               First Sibling              |nvim-tree-api.node.navigate.sibling.first()|
+`L`               Toggle Group Empty         |nvim-tree-api.node.open.toggle_group_empty()|
 `M`               Toggle Filter: No Bookmark |nvim-tree-api.tree.toggle_no_bookmark_filter()|
 `m`               Toggle Bookmark            |nvim-tree-api.marks.toggle()|
 `o`               Open                       |nvim-tree-api.node.open.edit()|
@@ -1848,6 +1849,12 @@ node.open.vertical()                      *nvim-tree-api.node.open.vertical()*
 node.open.horizontal()                  *nvim-tree-api.node.open.horizontal()*
     |nvim-tree-api.node.edit()|, file will be opened in a new horizontal split.
 
+                                *nvim-tree-api.node.open.toggle_group_empty()*
+node.open.toggle_group_empty()
+    Toggle |nvim-tree.renderer.group_empty| for a specific folder.
+    Does nothing on files.
+    Needs |nvim-tree.renderer.group_empty| set.
+
 node.open.drop()                              *nvim-tree-api.node.open.drop()*
     Switch to window with selected file if it exists.
     Open file otherwise.
@@ -2196,6 +2203,7 @@ You are encouraged to copy these to your own |nvim-tree.on_attach| function.
   vim.keymap.set('n', 'I',       api.tree.toggle_gitignore_filter,    opts('Toggle Filter: Git Ignore'))
   vim.keymap.set('n', 'J',       api.node.navigate.sibling.last,      opts('Last Sibling'))
   vim.keymap.set('n', 'K',       api.node.navigate.sibling.first,     opts('First Sibling'))
+  vim.keymap.set('n', 'L',       api.node.open.toggle_group_empty,    opts('Toggle Group Empty'))
   vim.keymap.set('n', 'M',       api.tree.toggle_no_bookmark_filter,  opts('Toggle Filter: No Bookmark'))
   vim.keymap.set('n', 'm',       api.marks.toggle,                    opts('Toggle Bookmark'))
   vim.keymap.set('n', 'o',       api.node.open.edit,                  opts('Open'))

lua/nvim-tree/api.lua

@@ -175,13 +175,13 @@ end
 
 ---@param mode string
 ---@return fun(node: table)
-local function open_or_expand_or_dir_up(mode)
+local function open_or_expand_or_dir_up(mode, toggle_group)
   return function(node)
     if node.name == ".." then
       actions.root.change_dir.fn ".."
     elseif node.nodes then
-      lib.expand_or_collapse(node)
+      lib.expand_or_collapse(node, toggle_group)
-    else
+    elseif not toggle_group then
       edit(mode, node)
     end
   end
@@ -195,6 +195,7 @@ Api.node.open.no_window_picker = wrap_node(open_or_expand_or_dir_up "edit_no_pic
 Api.node.open.vertical = wrap_node(open_or_expand_or_dir_up "vsplit")
 Api.node.open.horizontal = wrap_node(open_or_expand_or_dir_up "split")
 Api.node.open.tab = wrap_node(open_or_expand_or_dir_up "tabnew")
+Api.node.open.toggle_group_empty = wrap_node(open_or_expand_or_dir_up("toggle_group_empty", true))
 Api.node.open.preview = wrap_node(open_or_expand_or_dir_up "preview")
 Api.node.open.preview_no_picker = wrap_node(open_or_expand_or_dir_up "preview_no_picker")
 

lua/nvim-tree/keymap.lua

@@ -72,6 +72,7 @@ function M.default_on_attach(bufnr)
   vim.keymap.set('n', 'I',       api.tree.toggle_gitignore_filter,    opts('Toggle Filter: Git Ignore'))
   vim.keymap.set('n', 'J',       api.node.navigate.sibling.last,      opts('Last Sibling'))
   vim.keymap.set('n', 'K',       api.node.navigate.sibling.first,     opts('First Sibling'))
+  vim.keymap.set('n', 'L',       api.node.open.toggle_group_empty,    opts('Toggle Group Empty'))
   vim.keymap.set('n', 'M',       api.tree.toggle_no_bookmark_filter,  opts('Toggle Filter: No Bookmark'))
   vim.keymap.set('n', 'm',       api.marks.toggle,                    opts('Toggle Bookmark'))
   vim.keymap.set('n', 'o',       api.node.open.edit,                  opts('Open'))

lua/nvim-tree/lib.lua

@@ -3,6 +3,7 @@ local view = require "nvim-tree.view"
 local core = require "nvim-tree.core"
 local utils = require "nvim-tree.utils"
 local events = require "nvim-tree.events"
+local explorer_node = require "nvim-tree.explorer.node"
 
 ---@class LibOpenOpts
 ---@field path string|nil path
@@ -86,6 +87,34 @@ function M.get_last_group_node(node)
   return node
 end
 
+---Group empty folders
+-- Recursively group nodes
+---@param node Node
+---@return Node[]
+function M.group_empty_folders(node)
+  local is_root = not node.parent
+  local child_folder_only = explorer_node.has_one_child_folder(node) and node.nodes[1]
+  if M.group_empty and not is_root and child_folder_only then
+    node.group_next = child_folder_only
+    local ns = M.group_empty_folders(child_folder_only)
+    node.nodes = ns or {}
+    return ns
+  end
+  return node.nodes
+end
+
+---Ungroup empty folders
+-- If a node is grouped, ungroup it: put node.group_next to the node.nodes and set node.group_next to nil
+---@param node Node
+function M.ungroup_empty_folders(node)
+  local cur = node
+  while cur and cur.group_next do
+    cur.nodes = { cur.group_next }
+    cur.group_next = nil
+    cur = cur.nodes[1]
+  end
+end
+
 ---@param node Node
 ---@return Node[]
 function M.get_all_nodes_in_group(node)
@@ -98,8 +127,21 @@ function M.get_all_nodes_in_group(node)
   return nodes
 end
 
+-- Toggle group empty folders
+---@param head_node Node
+local function toggle_group_folders(head_node)
+  local is_grouped = head_node.group_next ~= nil
+
+  if is_grouped then
+    M.ungroup_empty_folders(head_node)
+  else
+    M.group_empty_folders(head_node)
+  end
+end
+
 ---@param node Node
-function M.expand_or_collapse(node)
+function M.expand_or_collapse(node, toggle_group)
+  toggle_group = toggle_group or false
   if node.has_children then
     node.has_children = false
   end
@@ -108,9 +150,20 @@ function M.expand_or_collapse(node)
     core.get_explorer():expand(node)
   end
 
-  local open = not M.get_last_group_node(node).open
+  local head_node = utils.get_parent_of_group(node)
-  for _, n in ipairs(M.get_all_nodes_in_group(node)) do
+  if toggle_group then
-    n.open = open
+    toggle_group_folders(head_node)
+  end
+
+  local open = M.get_last_group_node(node).open
+  local next_open
+  if toggle_group then
+    next_open = open
+  else
+    next_open = not open
+  end
+  for _, n in ipairs(M.get_all_nodes_in_group(head_node)) do
+    n.open = next_open
   end
 
   renderer.draw()
@@ -213,6 +266,7 @@ function M.setup(opts)
   M.hijack_directories = opts.hijack_directories
   M.respect_buf_cwd = opts.respect_buf_cwd
   M.select_prompts = opts.select_prompts
+  M.group_empty = opts.renderer.group_empty
 end
 
 return M