feat(#2654): filters.custom may be a function

doc/nvim-tree-lua.txt

@@ -1262,7 +1262,7 @@ Enabling this is not useful as there is no means yet to persist bookmarks.
 Custom list of vim regex for file/directory names that will not be shown.
 Backslashes must be escaped e.g. "^\\.git". See |string-match|.
 Toggle via |nvim-tree-api.tree.toggle_custom_filter()|, default `U`
-  Type: {string}, Default: `{}`
+  Type: {string} | `function(absolute_path)`, Default: `{}`
 
 *nvim-tree.filters.exclude*
 List of directories or files to exclude from filtering: always show them.

lua/nvim-tree.lua

@@ -623,6 +623,9 @@ local ACCEPTED_TYPES = {
     group_empty = { "boolean", "function" },
     root_folder_label = { "function", "string", "boolean" },
   },
+  filters = {
+    custom = { "function" },
+  },
   actions = {
     open_file = {
       window_picker = {

lua/nvim-tree/explorer/filters.lua

@@ -4,6 +4,7 @@ local marks = require "nvim-tree.marks"
 local M = {
   ignore_list = {},
   exclude_list = {},
+  custom_function = nil,
 }
 
 ---@param path string
@@ -84,6 +85,11 @@ local function custom(path)
 
   local basename = utils.path_basename(path)
 
+  -- filter user's custom function
+  if M.custom_function and M.custom_function(path) then
+    return true
+  end
+
   -- filter custom regexes
   local relpath = utils.path_relative(path, vim.loop.cwd())
   for pat, _ in pairs(M.ignore_list) do
@@ -153,9 +159,13 @@ function M.setup(opts)
   M.exclude_list = opts.filters.exclude
 
   local custom_filter = opts.filters.custom
-  if custom_filter and #custom_filter > 0 then
-    for _, filter_name in pairs(custom_filter) do
-      M.ignore_list[filter_name] = true
+  if type(custom_filter) == "function" then
+    M.custom_function = custom_filter
+  else
+    if custom_filter and #custom_filter > 0 then
+      for _, filter_name in pairs(custom_filter) do
+        M.ignore_list[filter_name] = true
+      end
     end
   end
 end