feat: add TreePreOpen event

doc/nvim-tree-lua.txt

@@ -2769,13 +2769,25 @@ e.g. handler for node renamed: >lua
 |nvim_tree_events_kind|
 
 - Event.Ready
-                When NvimTree has been initialized
+                When NvimTree has been initialized.
+                • Note: Handler takes no parameter.
+
+- Event.TreePreOpen
+                Invoked before the window and buffer for NvimTree are created
+                or opened. Before |Event.TreeOpen| event.
                 • Note: Handler takes no parameter.
 
 - Event.TreeOpen
+                Invoked after the NvimTree is opened.
+                • Note: Handler takes no parameter.
+
+- Event.TreePreClose
+                Invoked before the window and buffer for NvimTree are closed.
+                Before |Event.TreeClose| event.
                 • Note: Handler takes no parameter.
 
 - Event.TreeClose
+                Invoked after the NvimTree is closed.
                 • Note: Handler takes no parameter.
 
 - Event.Resize - When NvimTree is resized.

lua/nvim-tree/events.lua

@@ -8,7 +8,9 @@ M.Event = {
   Ready = "Ready",
   WillRenameNode = "WillRenameNode",
   NodeRenamed = "NodeRenamed",
+  TreePreOpen = "TreePreOpen",
   TreeOpen = "TreeOpen",
+  TreePreClose = "TreePreClose",
   TreeClose = "TreeClose",
   WillCreateFile = "WillCreateFile",
   FileCreated = "FileCreated",
@@ -91,11 +93,21 @@ function M._dispatch_folder_removed(folder_name)
   dispatch(M.Event.FolderRemoved, { folder_name = folder_name })
 end
 
+--@private
+function M._dispatch_on_tree_pre_open()
+  dispatch(M.Event.TreePreOpen, nil)
+end
+
 --@private
 function M._dispatch_on_tree_open()
   dispatch(M.Event.TreeOpen, nil)
 end
 
+--@private
+function M._dispatch_on_tree_pre_close()
+  dispatch(M.Event.TreePreClose, nil)
+end
+
 --@private
 function M._dispatch_on_tree_close()
   dispatch(M.Event.TreeClose, nil)

lua/nvim-tree/lib.lua

@@ -109,6 +109,7 @@ function M.open(opts)
 
   local explorer = core.get_explorer()
 
+  events._dispatch_on_tree_pre_open()
   if should_hijack_current_buf() then
     view.close_this_tab_only()
     view.open_in_win()

lua/nvim-tree/view.lua

@@ -238,6 +238,7 @@ local function close(tabpage)
     return
   end
   save_tab_state(tabpage)
+  events._dispatch_on_tree_pre_close()
   switch_buf_if_last_buf()
   local tree_win = M.get_winnr(tabpage)
   local current_win = vim.api.nvim_get_current_win()
@@ -288,6 +289,7 @@ function M.open(options)
 
   local profile = log.profile_start("view open")
 
+  events._dispatch_on_tree_pre_open()
   create_buffer()
   open_window()
   M.resize()