From 170629ba14aba36e678538dbb384d8424d1c9cf8 Mon Sep 17 00:00:00 2001
From: muro3r <10064571+muro3r@users.noreply.github.com>
Date: Sat, 14 May 2022 16:54:37 +0900
Subject: [PATCH] feat: extension sorter (#1181)

---
 doc/nvim-tree-lua.txt              |  2 +-
 lua/nvim-tree/explorer/sorters.lua | 26 ++++++++++++++++++++++++++
 2 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/doc/nvim-tree-lua.txt b/doc/nvim-tree-lua.txt
index bf4927f11ee..04ce7f267f9 100644
--- a/doc/nvim-tree-lua.txt
+++ b/doc/nvim-tree-lua.txt
@@ -244,7 +244,7 @@ if the tree was previously open.
 
 *nvim-tree.sort_by*
 Changes how files within the same directory are sorted.
-Can be one of 'name', 'case_sensitive' or 'modification_time'.
+Can be one of 'name', 'case_sensitive', 'modification_time' or 'extension'.
   Type: `string`, Default: `"name"`
 
 *nvim-tree.hijack_unnamed_buffer_when_opening*
diff --git a/lua/nvim-tree/explorer/sorters.lua b/lua/nvim-tree/explorer/sorters.lua
index e82cba0061c..4168a931c95 100644
--- a/lua/nvim-tree/explorer/sorters.lua
+++ b/lua/nvim-tree/explorer/sorters.lua
@@ -124,12 +124,38 @@ function M.node_comparator_modification_time(a, b)
   return last_modified_b <= last_modified_a
 end
 
+function M.node_comparator_extension(a, b)
+  if not (a and b) then
+    return true
+  end
+
+  if a.nodes and not b.nodes then
+    return true
+  elseif not a.nodes and b.nodes then
+    return false
+  end
+
+  if not (a.extension and b.extension) then
+    return true
+  end
+
+  if a.extension and not b.extension then
+    return true
+  elseif not a.extension and b.extension then
+    return false
+  end
+
+  return a.extension:lower() <= b.extension:lower()
+end
+
 function M.setup(opts)
   M.sort_by = opts.sort_by
   if M.sort_by == "modification_time" then
     M.node_comparator = M.node_comparator_modification_time
   elseif M.sort_by == "case_sensitive" then
     M.node_comparator = M.node_comparator_name_case_sensisive
+  elseif M.sort_by == "extension" then
+    M.node_comparator = M.node_comparator_extension
   else
     M.node_comparator = M.node_comparator_name_ignorecase
   end