diff --git a/lua/config/lsp.lua b/lua/config/lsp.lua
index 9ead5e5..b5fab6a 100644
--- a/lua/config/lsp.lua
+++ b/lua/config/lsp.lua
@@ -1,3 +1,4 @@
+local fn = vim.fn
 local api = vim.api
 local lsp = vim.lsp
 
@@ -135,9 +136,9 @@ if utils.executable('bash-language-server') then
   })
 end
 
-local sumneko_binary_path = vim.fn.exepath("lua-language-server")
+local sumneko_binary_path = fn.exepath("lua-language-server")
 if vim.g.is_mac or vim.g.is_linux and sumneko_binary_path ~= "" then
-  local sumneko_root_path = vim.fn.fnamemodify(sumneko_binary_path, ":h:h:h")
+  local sumneko_root_path = fn.fnamemodify(sumneko_binary_path, ":h:h:h")
 
   local runtime_path = vim.split(package.path, ";")
   table.insert(runtime_path, "lua/?.lua")
@@ -173,10 +174,10 @@ if vim.g.is_mac or vim.g.is_linux and sumneko_binary_path ~= "" then
 end
 
 -- Change diagnostic signs.
-vim.fn.sign_define("DiagnosticSignError", { text = "✗", texthl = "DiagnosticSignError" })
-vim.fn.sign_define("DiagnosticSignWarn", { text = "!", texthl = "DiagnosticSignWarn" })
-vim.fn.sign_define("DiagnosticSignInformation", { text = "", texthl = "DiagnosticSignInfo" })
-vim.fn.sign_define("DiagnosticSignHint", { text = "", texthl = "DiagnosticSignHint" })
+fn.sign_define("DiagnosticSignError", { text = "✗", texthl = "DiagnosticSignError" })
+fn.sign_define("DiagnosticSignWarn", { text = "!", texthl = "DiagnosticSignWarn" })
+fn.sign_define("DiagnosticSignInformation", { text = "", texthl = "DiagnosticSignInfo" })
+fn.sign_define("DiagnosticSignHint", { text = "", texthl = "DiagnosticSignHint" })
 
 -- global config for diagnostic
 vim.diagnostic.config({
diff --git a/lua/config/statusline.lua b/lua/config/statusline.lua
index 85e6e46..ff69060 100644
--- a/lua/config/statusline.lua
+++ b/lua/config/statusline.lua
@@ -1,3 +1,5 @@
+local fn = vim.fn
+
 local function spell()
   if vim.o.spell then
     return string.format("[SPELL]")
@@ -9,7 +11,7 @@ end
 local function ime_state()
   if vim.g.is_mac then
     -- ref: https://github.com/vim-airline/vim-airline/blob/master/autoload/airline/extensions/xkblayout.vim#L11
-    local layout = vim.fn.libcall(vim.g.XkbSwitchLib, 'Xkb_Switch_getXkbLayout', '')
+    local layout = fn.libcall(vim.g.XkbSwitchLib, 'Xkb_Switch_getXkbLayout', '')
     if layout == '0' then
       return '[CN]'
     end
@@ -35,20 +37,20 @@ end
 local function mixed_indent()
   local space_pat = [[\v^ +]]
   local tab_pat = [[\v^\t+]]
-  local space_indent = vim.fn.search(space_pat, 'nwc')
-  local tab_indent = vim.fn.search(tab_pat, 'nwc')
+  local space_indent = fn.search(space_pat, 'nwc')
+  local tab_indent = fn.search(tab_pat, 'nwc')
   local mixed = (space_indent > 0 and tab_indent > 0)
   local mixed_same_line
   if not mixed then
-    mixed_same_line = vim.fn.search([[\v^(\t+ | +\t)]], 'nwc')
+    mixed_same_line = fn.search([[\v^(\t+ | +\t)]], 'nwc')
     mixed = mixed_same_line > 0
   end
   if not mixed then return '' end
   if mixed_same_line ~= nil and mixed_same_line > 0 then
      return 'MI:'..mixed_same_line
   end
-  local space_indent_cnt = vim.fn.searchcount({pattern=space_pat, max_count=1e3}).total
-  local tab_indent_cnt =  vim.fn.searchcount({pattern=tab_pat, max_count=1e3}).total
+  local space_indent_cnt = fn.searchcount({pattern=space_pat, max_count=1e3}).total
+  local tab_indent_cnt =  fn.searchcount({pattern=tab_pat, max_count=1e3}).total
   if space_indent_cnt > tab_indent_cnt then
     return 'MI:'..tab_indent
   else
diff --git a/lua/plugins.lua b/lua/plugins.lua
index 6065efb..9376e91 100644
--- a/lua/plugins.lua
+++ b/lua/plugins.lua
@@ -359,7 +359,7 @@ require("packer").startup({
   end,
   config = {
     max_jobs = 16,
-    compile_path = util.join_paths(vim.fn.stdpath('data'), 'site', 'lua', 'packer_compiled.lua'),
+    compile_path = util.join_paths(fn.stdpath('data'), 'site', 'lua', 'packer_compiled.lua'),
   },
 })
 
diff --git a/lua/utils.lua b/lua/utils.lua
index c04f64b..a6fd11a 100644
--- a/lua/utils.lua
+++ b/lua/utils.lua
@@ -1,3 +1,5 @@
+local fn = vim.fn
+
 -- inspect something
 function inspect(item)
   vim.pretty_print(item)
@@ -6,7 +8,7 @@ end
 local M = {}
 
 function M.executable(name)
-  if vim.fn.executable(name) > 0 then
+  if fn.executable(name) > 0 then
     return true
   end
 
@@ -14,12 +16,12 @@ function M.executable(name)
 end
 
 function M.may_create_dir()
-  local fpath = vim.fn.expand('<afile>')
-  local parent_dir = vim.fn.fnamemodify(fpath, ":p:h")
-  local res = vim.fn.isdirectory(parent_dir)
+  local fpath = fn.expand('<afile>')
+  local parent_dir = fn.fnamemodify(fpath, ":p:h")
+  local res = fn.isdirectory(parent_dir)
 
   if res == 0 then
-    vim.fn.mkdir(parent_dir, 'p')
+    fn.mkdir(parent_dir, 'p')
   end
 end