feat: Add ability to customize notification handler

Author: ghostbuster91

doc/nvim-tree-lua.txt

@@ -440,6 +440,7 @@ applying configuration.
       },
       notify = {
         threshold = vim.log.levels.INFO,
+        handler = "default",
       },
       ui = {
         confirm = {
@@ -1224,6 +1225,18 @@ Configuration for notification.
     `INFO:`    information only e.g. file copy path confirmation.
     `DEBUG:`   not used.
 
+    *nvim-tree.notify.handler*
+    Change the default notification handler, can be a string `"default"` or a function.
+    The default handler will check if the nvim-notify plugin is present on the
+    runtime path and use it, otherwise it will fallback to use `vim.notify`. 
+      Type: `string` | `function`, Default: `"default"`
+
+    The function will be called with following parameters:
+
+    `msg`:    notification message
+    `level`:  notification level (see `vim.log.levels` for possible values)
+    `opts`:   table with additional parameters (e.g. `title`)
+
 *nvim-tree.ui*
 General UI configuration.
 

lua/nvim-tree.lua

@@ -629,6 +629,7 @@ local DEFAULT_OPTS = { -- BEGIN_DEFAULT_OPTS
   },
   notify = {
     threshold = vim.log.levels.INFO,
+    handler = "default",
   },
   ui = {
     confirm = {
@@ -674,6 +675,7 @@ local FIELD_OVERRIDE_TYPECHECK = {
   sort_by = { ["function"] = true, string = true },
   root_folder_label = { ["function"] = true, string = true },
   picker = { ["function"] = true, string = true },
+  handler = { ["function"] = true, string = true },
 }
 
 local function validate_options(conf)

lua/nvim-tree/notify.lua

@@ -1,5 +1,9 @@
 local M = {}
 
+local fallback_handler = function(msg, level, opts)
+  vim.notify(string.format("[%s] %s", opts.title, vim.inspect(msg)), level)
+end
+
 local config = {
   threshold = vim.log.levels.INFO,
 }
@@ -13,19 +17,13 @@ local modes = {
 }
 
 do
-  local has_notify, notify_plugin = pcall(require, "notify")
-
   local dispatch = function(level, msg)
     if level < config.threshold then
       return
     end
 
     vim.schedule(function()
-      if has_notify and notify_plugin then
-        notify_plugin(msg, level, { title = "NvimTree" })
-      else
-        vim.notify(string.format("[NvimTree] %s", vim.inspect(msg)), level)
-      end
+      config.handler(msg, level, { title = "NvimTree" })
     end)
   end
 
@@ -36,9 +34,23 @@ do
   end
 end
 
+local create_default_handler = function()
+  local has_notify, notify_plugin = pcall(require, "notify")
+  if has_notify and notify_plugin then
+    return notify_plugin
+  else
+    return fallback_handler
+  end
+end
+
 function M.setup(opts)
   opts = opts or {}
   config.threshold = opts.notify.threshold or vim.log.levels.INFO
+  if type(opts.notify.handler) == "function" then
+    config.handler = opts.notify.handler
+  else
+    config.handler = create_default_handler()
+  end
 end
 
 return M