add existence checks and undos

Author: Konfekt

ftplugin/svelte.vim

@@ -1,8 +1,11 @@
 if exists("b:did_ftplugin") | finish | endif
 let b:did_ftplugin = 1
 
+let b:undo_ftplugin = get(b:, 'undo_ftplugin', '')
+
 if !has('nvim')
   setlocal matchpairs+=<:>
+  let b:undo_ftplugin .= "| setlocal matchpairs<"
 endif
 
 if exists("loaded_matchit")
@@ -13,18 +16,24 @@ if exists("loaded_matchit")
         \ '<\@<=\([^/][^ \t>]*\)[^>]*\%(>\|$\):<\@<=/\1>,' .
         \ '{#\(if\|each\)[^}]*}:{\:else[^}]*}:{\/\(if\|each\)},' .
         \ '{#await[^}]*}:{\:then[^}]*}:{\/await},'
+  let b:undo_ftplugin .= "| unlet b:match_ignorecase b:match_words"
 endif
 
 " Indent correctly with template string for vim-javascript/builtin
 " indentexpr
 let b:syng_str = '^\%(.*template\)\@!.*string\|special'
 let b:syng_strcom = '^\%(.*template\)\@!.*string\|comment\|regex\|special\|doc'
+let b:undo_ftplugin .= "| unlet b:syng_str b:syng_strcom"
 
-if executable('npx')
+if executable('npx') && !empty(globpath(&runtimepath, 'compiler/svelte-check.vim'))
   compiler svelte-check
+  let b:undo_ftplugin .= "| compiler make"
 endif
-" let &keywordprg = ':Open https://devdocs.io/\#q='..&filetype
-nnoremap <buffer> <expr> <F1> '<cmd>Open https://devdocs.io/\#q='..&filetype..' '..expand('<cword>')..'<CR>'
-if exists('*getregion')
-  vnoremap <buffer> <expr> <F1> '<cmd>Open https://devdocs.io/\#q='..&filetype..' '..join(getregion(getpos('v'), getpos('.')))..'<CR>'
+if exists(':Open') == 2
+  " let &keywordprg = ':Open https://devdocs.io/\#q='..&filetype
+  nnoremap <buffer> <expr> <F1> '<cmd>Open https://devdocs.io/\#q='..&filetype..' '..expand('<cword>')..'<CR>'
+  if exists('*getregion')
+    vnoremap <buffer> <expr> <F1> '<cmd>Open https://devdocs.io/\#q='..&filetype..' '..join(getregion(getpos('v'), getpos('.')))..'<CR>'
+  endif
+  let b:undo_ftplugin .= "| nunmap <buffer> <F1> | vnunmap <buffer> <F1>"
 endif