use [func]

Author: mattn

autoload/lsp_settings.vim

@@ -79,18 +79,14 @@ endfunction
 
 function! s:get_filetype_default(ft) abort
   let l:default = get(g:, 'lsp_settings_filetype_' . a:ft, '')
-  if type(l:default) ==# v:t_list
-    for l:i in range(len(l:default))
-      let l:V = l:default[l:i]
-      if type(l:V) ==# v:t_func
-        try
-          let l:default[l:i] = l:V()
-        catch
-          let l:default[l:i] = ''
-        endtry
-      endif
-    endfor
-    let g:['lsp_settings_filetype_' . a:ft] = l:default
+  if type(l:default) ==# v:t_list && len(l:default) == 1 && type(l:default[0]) == v:t_func
+    let l:V = l:default[0]
+    try
+      let l:default = l:V()
+      let g:['lsp_settings_filetype_' . a:ft] = l:default
+    catch
+      let l:default = ''
+    endtry
   endif
   return l:default
 endfunction

doc/vim-lsp-settings.txt

@@ -161,6 +161,17 @@ g:lsp_settings_deny_local_keys
   This variable is specified name of settings like 'cmd' to drop items in the
   settings.
 
+                                                 *g:lsp_settings_filetype_xxx*
+g:lsp_settings_filetype_xxx
+  xxx is a filetype name like typescript with: >
+    g:lsp_settings_filetype_typescript
+<
+  This variable can specify default language server. If the variable is a
+  |string|, vim-lsp-settings load the langage server name. If the variable is
+  a |list|, all of the language server names are loaded.  If the variable have
+  one element and type of the element is |function|, vim-lsp-settings call it
+  and the result is evaluated lazy.
+
 :LspSettingsLocalEdit [root]                           *:LspSettingsLocalEdit*
   Edit local settings. Accepts an optional explicit [root] directory that
   contains the .vim-lsp-settings config directory.