Add set_cache function

lua/hardline/common.lua

@@ -35,4 +35,11 @@ function M.get_state(class)
   return M.is_active() and 'active' or 'inactive'
 end
 
+function M.set_cache(augroup)
+  cmd(string.format('augroup %s', augroup))
+  cmd('autocmd!')
+  cmd(string.format('autocmd CursorHold,BufWritePost * unlet! b:%s', augroup))
+  cmd('augroup END')
+end
+
 return M

lua/hardline/parts/whitespace.lua

@@ -1,5 +1,6 @@
 local cmd, fn, vim = vim.cmd, vim.fn, vim
 local b, bo = vim.b, vim.bo
+local common = require('hardline.common')
 
 local enabled = false
 local cache = ''
@@ -49,10 +50,7 @@ end
 
 local function get_item()
   if not enabled then
-    cmd 'augroup hardline_whitespace'
-    cmd 'autocmd!'
-    cmd 'autocmd CursorHold,BufWritePost * unlet! b:hardline_whitespace'
-    cmd 'augroup END'
+    common.set_cache('hardline_whitespace')
     enabled = true
   end
   if bo.readonly or not bo.modifiable then return '' end

lua/hardline/parts/wordcount.lua

@@ -33,10 +33,7 @@ end
 
 local function get_item()
   if not enabled then
-    cmd 'augroup hardline_wordcount'
-    cmd 'autocmd!'
-    cmd 'autocmd CursorHold,BufWritePost * unlet! b:hardline_wordcount'
-    cmd 'augroup END'
+    common.set_cache('hardline_wordcount')
     enabled = true
   end
   if not vim.tbl_contains(options.filetypes, bo.filetype) then return '' end