chore(iterators): create Iterator module and migrate iterators to use it (#1392)

lua/nvim-tree/actions/expand-all.lua

@@ -1,6 +1,7 @@
 local core = require "nvim-tree.core"
 local renderer = require "nvim-tree.renderer"
 local utils = require "nvim-tree.utils"
+local Iterator = require "nvim-tree.iterators.node-iterator"
 
 local M = {}
 
@@ -20,34 +21,38 @@ local function expand(node)
   end
 end
 
+local function should_expand(expansion_count, node)
+  local should_halt = expansion_count >= M.MAX_FOLDER_DISCOVERY
+  local should_exclude = M.EXCLUDE[node.name]
+  return not should_halt and node.nodes and not node.open and not should_exclude
+end
+
 local function gen_iterator()
   local expansion_count = 0
 
-  local function iterate(parent)
-    if expansion_count >= M.MAX_FOLDER_DISCOVERY then
-      return true
-    end
-
+  return function(parent)
     if parent.parent and parent.nodes and not parent.open then
       expansion_count = expansion_count + 1
       expand(parent)
     end
 
-    for _, node in pairs(parent.nodes) do
-      if node.nodes and not node.open and not M.EXCLUDE[node.name] then
-        expansion_count = expansion_count + 1
-        expand(node)
-      end
-
-      if node.open then
-        if iterate(node) then
-          return true
+    Iterator.builder(parent.nodes)
+      :hidden()
+      :applier(function(node)
+        if should_expand(expansion_count, node) then
+          expansion_count = expansion_count + 1
+          expand(node)
         end
-      end
+      end)
+      :recursor(function(node)
+        return expansion_count < M.MAX_FOLDER_DISCOVERY and node.open and node.nodes
+      end)
+      :iterate()
+
+    if expansion_count >= M.MAX_FOLDER_DISCOVERY then
+      return true
     end
   end
-
-  return iterate
 end
 
 function M.fn(base_node)