diff --git a/autoload/nerdcommenter.vim b/autoload/nerdcommenter.vim
index 8bc7c9f..6c81827 100644
--- a/autoload/nerdcommenter.vim
+++ b/autoload/nerdcommenter.vim
@@ -447,31 +447,20 @@ endif
 " Section: Comment mapping functions, autocommands and commands
 " ============================================================================
 
-" Function: nerdcommenter#SetUpForNewFiletype(filetype) function
+" Function: nerdcommenter#SetUp() function
 " This function is responsible for setting up buffer scoped variables for the
-" given filetype.
-"
-" Args:
-"   -filetype: the filetype to set delimiters for
-"   -forceReset: 1 if the delimiters should be reset if they have already be
-"    set for this buffer.
-"
-
-" used to avoid calculating things inside nerdcommenter#SetUpForNewFiletype
-let s:last_filetype = '_force_setup_the_first_time_'
-
-function! nerdcommenter#SetUpForNewFiletype(filetype, forceReset) abort
-    let filetype = a:filetype
-    if s:last_filetype == filetype
-        return 0
-    else
-        let s:last_filetype = filetype
+" current buffer.
+function! nerdcommenter#SetUp() abort
+    if exists('b:NERDCommenterDelims')
+        return
     endif
 
+    let filetype = &filetype
+
     "for compound filetypes, if we don't know how to handle the full filetype
     "then break it down and use the first part that we know how to handle
     if filetype =~# '\.' && !has_key(s:delimiterMap, filetype)
-        let filetypes = split(a:filetype, '\.')
+        let filetypes = split(filetype, '\.')
         for i in filetypes
             if has_key(s:delimiterMap, i)
                 let filetype = i
@@ -536,7 +525,7 @@ endfunction
 "    if this function changed the delimiters or not
 " function nerdcommenter#SwitchToAlternativeDelimiters(printMsgs)
 function! nerdcommenter#SwitchToAlternativeDelimiters(printMsgs) abort
-    call nerdcommenter#SetUpForNewFiletype(&filetype, 1)
+    call nerdcommenter#SetUp()
     if exists('*NERDCommenter_before')
         exe 'call NERDCommenter_before()'
     endif
@@ -1176,7 +1165,7 @@ endfunction
 "    'Minimal', 'Toggle', 'AlignLeft', 'AlignBoth', 'Comment',
 "    'Nested', 'ToEOL', 'Append', 'Insert', 'Uncomment', 'Yank'
 function! nerdcommenter#Comment(mode, type) range abort
-    call nerdcommenter#SetUpForNewFiletype(&filetype, 1)
+    call nerdcommenter#SetUp()
     if exists('*NERDCommenter_before')
         exe 'call NERDCommenter_before()'
     endif