From c24c0470d9de277fbebecd718f33561ed7c90298 Mon Sep 17 00:00:00 2001
From: Devansh Sharma <21225957+devansh08@users.noreply.github.com>
Date: Mon, 21 Apr 2025 04:09:48 +0530
Subject: [PATCH] feat: add TreePreOpen event (#3105)

* feat: Add `TreePreOpen` and `TreePreClose` events

* docs: Update docs for `TreePreOpen` and `TreePreClose` events

* chore: remove `TreePreClose` event and update dispatch of `TreePreOpen`

---------

Co-authored-by: Alexander Courtis <alex@courtis.org>
---
 doc/nvim-tree-lua.txt    | 10 +++++++++-
 lua/nvim-tree/events.lua |  6 ++++++
 lua/nvim-tree/view.lua   |  2 ++
 3 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/doc/nvim-tree-lua.txt b/doc/nvim-tree-lua.txt
index 2aa8422f..6de64558 100644
--- a/doc/nvim-tree-lua.txt
+++ b/doc/nvim-tree-lua.txt
@@ -2769,13 +2769,21 @@ 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.TreeClose
+                Invoked after the NvimTree is closed, but before the window is
+                closed. Dispatched on |WinClosed| event for NvimTree window.
                 • Note: Handler takes no parameter.
 
 - Event.Resize - When NvimTree is resized.
diff --git a/lua/nvim-tree/events.lua b/lua/nvim-tree/events.lua
index 7b57333a..e9dde833 100644
--- a/lua/nvim-tree/events.lua
+++ b/lua/nvim-tree/events.lua
@@ -8,6 +8,7 @@ M.Event = {
   Ready = "Ready",
   WillRenameNode = "WillRenameNode",
   NodeRenamed = "NodeRenamed",
+  TreePreOpen = "TreePreOpen",
   TreeOpen = "TreeOpen",
   TreeClose = "TreeClose",
   WillCreateFile = "WillCreateFile",
@@ -91,6 +92,11 @@ 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)
diff --git a/lua/nvim-tree/view.lua b/lua/nvim-tree/view.lua
index 94cf2987..41b98873 100644
--- a/lua/nvim-tree/view.lua
+++ b/lua/nvim-tree/view.lua
@@ -288,6 +288,7 @@ function M.open(options)
 
   local profile = log.profile_start("view open")
 
+  events._dispatch_on_tree_pre_open()
   create_buffer()
   open_window()
   M.resize()
@@ -413,6 +414,7 @@ end
 ---@param opts OpenInWinOpts|nil
 function M.open_in_win(opts)
   opts = opts or { hijack_current_buf = true, resize = true }
+  events._dispatch_on_tree_pre_open()
   if opts.winid and vim.api.nvim_win_is_valid(opts.winid) then
     vim.api.nvim_set_current_win(opts.winid)
   end