diff --git a/.editorconfig b/.editorconfig
new file mode 100644
index 0000000..b5ba17a
--- /dev/null
+++ b/.editorconfig
@@ -0,0 +1,13 @@
+root = true
+
+[*]
+indent_style = space
+indent_size = 2
+end_of_line = lf
+charset = utf-8
+trim_trailing_whitespace = true
+insert_final_newline = true
+max_line_length = off
+
+[*.{yaml,yml}]
+indent_size = 2
diff --git a/.github/workflows/linux_neovim.yml b/.github/workflows/linux_neovim.yml
index 18231a8..3c5ca68 100644
--- a/.github/workflows/linux_neovim.yml
+++ b/.github/workflows/linux_neovim.yml
@@ -46,4 +46,3 @@ jobs:
           themis ./spec
           export VIRTUALEDIT=1
           themis ./spec
-
diff --git a/README.md b/README.md
index dc7923c..bcec69b 100644
--- a/README.md
+++ b/README.md
@@ -23,6 +23,9 @@ VSCode(LSP)'s snippet feature in vim/nvim.
     - [vimcomplete](https://github.com/girishji/vimcomplete)
     - [ddc.vim](https://github.com/Shougo/ddc.vim)
     - [vim-easycompletion](https://github.com/jayli/vim-easycomplete)
+- Support built-in completion
+  - A function can be registered for finding completions.
+    `set complete+=Fvsnip#completefunc`
 - Vim script interpolation
   - You can use Vim script interpolation as `${VIM:...Vim script expression...}`.
 - SnipMate-like syntax support
@@ -120,7 +123,7 @@ The snippet format was described in [here](https://code.visualstudio.com/docs/ed
 
 # Recipe
 
-### $TM_FILENAME_BASE
+### $TM\_FILENAME\_BASE
 
 You can insert the filename via `fname\<Plug>(vsnip-expand)`.
 
@@ -133,7 +136,7 @@ You can insert the filename via `fname\<Plug>(vsnip-expand)`.
 }
 ```
 
-### Log $TM_SELECTED_TEXT
+### Log $TM\_SELECTED\_TEXT
 
 You can fill `$TM_SELECTED_TEXT` by `<Plug>(vsnip-select-text)` or `<Plug>(vsnip-cut-text)`.
 
@@ -197,4 +200,3 @@ You can run `npm run test` after install [vim-themis](https://github.com/thinca/
 1. compute the `user-diff` ... `s:Session.flush_changes`
 2. reflect the `user-diff` to snippet ast ... `s:Snippet.follow`
 3. reflect the `sync-diff` to buffer content ... `s:Snippet.sync & s:Session.flush_changes`
-
diff --git a/autoload/vital/_vsnip/VS/LSP/TextEdit.vim b/autoload/vital/_vsnip/VS/LSP/TextEdit.vim
index 968f8d5..d4a3f36 100644
--- a/autoload/vital/_vsnip/VS/LSP/TextEdit.vim
+++ b/autoload/vital/_vsnip/VS/LSP/TextEdit.vim
@@ -28,16 +28,21 @@ endfunction
 " apply
 "
 function! s:apply(path, text_edits) abort
-  let l:current_bufname = bufname('%')
-  let l:current_position = s:Position.cursor()
+  let l:current_bufnr = bufnr('%')
+  for l:bufnr in range(1, bufnr('$'))
+    if index([fnamemodify(a:path, ':p'),fnameescape(fnamemodify(a:path, ':p'))], bufname(l:bufnr)) != -1
+      let l:target_bufnr = l:bufnr
+      break
+    endif
+  endfor
+  if !exists('l:target_bufnr')
+    let l:target_bufnr = s:Buffer.ensure(a:path)
+  endif
 
-  let l:target_bufnr = s:_switch(a:path)
-  call s:_substitute(l:target_bufnr, a:text_edits, l:current_position)
-  let l:current_bufnr = s:_switch(l:current_bufname)
+  let l:current_position = s:Position.cursor()
+  call s:Buffer.do(l:target_bufnr, { -> s:_substitute(l:target_bufnr, a:text_edits, l:current_position) })
 
-  if l:current_bufnr == l:target_bufnr
-    call cursor(s:Position.lsp_to_vim('%', l:current_position))
-  endif
+  call cursor(s:Position.lsp_to_vim('%', l:current_position))
 endfunction
 
 "
@@ -167,19 +172,3 @@ function! s:_fix_text_edits(bufnr, text_edits) abort
   return [l:fixeol, l:text_edits]
 endfunction
 
-"
-" _switch
-"
-function! s:_switch(path) abort
-  let l:curr = bufnr('%')
-  let l:next = filereadable(a:path) ? bufnr(fnameescape(a:path)) : bufnr(a:path)
-  if l:next >= 0
-    if l:curr != l:next
-      execute printf('noautocmd keepalt keepjumps %sbuffer!', l:next)
-    endif
-  else
-    execute printf('noautocmd keepalt keepjumps edit! %s', fnameescape(a:path))
-  endif
-  return bufnr('%')
-endfunction
-
diff --git a/autoload/vital/vsnip.vital b/autoload/vital/vsnip.vital
index 8f293cd..f1d4801 100644
--- a/autoload/vital/vsnip.vital
+++ b/autoload/vital/vsnip.vital
@@ -1,5 +1,5 @@
 vsnip
-f28b0d147b702686817da56eef47e0736f425233
+4d4bb61bb1f9b3ac6cd679e3551de88ad3682cc3
 
 VS.LSP.TextEdit
 VS.LSP.Diff
diff --git a/autoload/vsnip.vim b/autoload/vsnip.vim
index 8069eee..6ccf4b0 100644
--- a/autoload/vsnip.vim
+++ b/autoload/vsnip.vim
@@ -166,6 +166,25 @@ function! vsnip#get_context() abort
   return {}
 endfunction
 
+"
+" vsnip#completefunc
+"
+function! vsnip#completefunc(findstart, base) abort
+  if !a:findstart
+    if a:base ==# ''
+      return []
+    endif
+    return vsnip#get_complete_items(bufnr('%'))
+  endif
+
+  let line = getline('.')
+  let start = col('.') - 2
+  while start >= 0 && line[start] =~# '\k'
+    let start -= 1
+  endwhile
+  return start + 1
+endfunction
+
 "
 " vsnip#get_complete_items
 "
diff --git a/autoload/vsnip/indent.vim b/autoload/vsnip/indent.vim
index 6222dd8..98c0bf2 100644
--- a/autoload/vsnip/indent.vim
+++ b/autoload/vsnip/indent.vim
@@ -58,4 +58,3 @@ function! vsnip#indent#trim_base_indent(text) abort
   endfor
   return substitute(l:text, "\\%(^\\|\n\\)\\zs\\V" . l:base_indent, '', 'g')
 endfunction
-
diff --git a/autoload/vsnip/parser/combinator.vim b/autoload/vsnip/parser/combinator.vim
index 59bfd83..7d4b06c 100644
--- a/autoload/vsnip/parser/combinator.vim
+++ b/autoload/vsnip/parser/combinator.vim
@@ -220,4 +220,3 @@ function! s:getchar(text, pos) abort
   endif
   return ''
 endfunction
-
diff --git a/autoload/vsnip/range.vim b/autoload/vsnip/range.vim
index 8ba5321..868ba8f 100644
--- a/autoload/vsnip/range.vim
+++ b/autoload/vsnip/range.vim
@@ -7,4 +7,3 @@ function! vsnip#range#cover(whole_range, target_range) abort
   let l:cover = l:cover && (a:target_range.end.line < a:whole_range.end.line || a:target_range.end.line == a:whole_range.end.line && a:target_range.end.character <= a:whole_range.end.character)
   return l:cover
 endfunction
-
diff --git a/autoload/vsnip/session.vim b/autoload/vsnip/session.vim
index 58c6fc3..e716e08 100644
--- a/autoload/vsnip/session.vim
+++ b/autoload/vsnip/session.vim
@@ -257,4 +257,3 @@ function! s:Session.store(changenr) abort
   \ }
   let self.changenr = a:changenr
 endfunction
-
diff --git a/autoload/vsnip/snippet/node/transform.vim b/autoload/vsnip/snippet/node/transform.vim
index f241fc8..64c6280 100644
--- a/autoload/vsnip/snippet/node/transform.vim
+++ b/autoload/vsnip/snippet/node/transform.vim
@@ -36,7 +36,7 @@ function! s:Transform.text(input_text) abort
   endif
 
   let l:text = ''
- 
+
   for l:replacement in self.replacements
     if l:replacement.type ==# 'format'
       if l:replacement.modifier ==# '/capitalize'
diff --git a/autoload/vsnip/snippet/node/variable.vim b/autoload/vsnip/snippet/node/variable.vim
index 4de1e48..4442d75 100644
--- a/autoload/vsnip/snippet/node/variable.vim
+++ b/autoload/vsnip/snippet/node/variable.vim
@@ -60,4 +60,3 @@ function! s:Variable.to_string() abort
   \   self.text()
   \ )
 endfunction
-
diff --git a/autoload/vsnip/snippet/parser.vim b/autoload/vsnip/snippet/parser.vim
index be0d1dc..44873ee 100644
--- a/autoload/vsnip/snippet/parser.vim
+++ b/autoload/vsnip/snippet/parser.vim
@@ -5,15 +5,15 @@ let s:Combinator = vsnip#parser#combinator#import()
 " @see https://github.com/Microsoft/language-server-protocol/blob/master/snippetSyntax.md
 "
 function! vsnip#snippet#parser#parse(text) abort
-	if strlen(a:text) == 0
-		return []
-	endif
+  if strlen(a:text) == 0
+    return []
+  endif
 
-	let l:parsed = s:parser.parse(a:text, 0)
-	if !l:parsed[0]
-		throw json_encode({ 'text': a:text, 'result': l:parsed })
-	endif
-	return l:parsed[1]
+  let l:parsed = s:parser.parse(a:text, 0)
+  if !l:parsed[0]
+    throw json_encode({ 'text': a:text, 'result': l:parsed })
+  endif
+  return l:parsed[1]
 endfunction
 
 let s:skip = s:Combinator.skip
@@ -209,4 +209,3 @@ let s:choice = s:map(s:seq(
 " parser.
 "
 let s:parser = s:many(s:or(s:any, s:text(['$'], ['}'])))
-
diff --git a/autoload/vsnip/source.vim b/autoload/vsnip/source.vim
index a6dc972..28df252 100644
--- a/autoload/vsnip/source.vim
+++ b/autoload/vsnip/source.vim
@@ -21,9 +21,28 @@ endfunction
 "
 " vsnip#source#filetypes
 "
-function! vsnip#source#filetypes(bufnr) abort
-  let l:filetype = getbufvar(a:bufnr, '&filetype', '')
-  return split(l:filetype, '\.') + get(g:vsnip_filetypes, l:filetype, []) + ['global']
+function! vsnip#source#filetypes( bufnr ) abort
+  if has( "nvim" )
+    let l:filetypes = v:lua.require'vsnip.treesitter'.get_ft_at_cursor( a:bufnr )
+
+    " buffer has no filetype defined
+    if l:filetypes.filetype == ""
+      return [ "global" ]
+
+    " buffer has filetype
+    else
+      return
+        \ get( g:vsnip_filetypes, l:filetypes.injected_filetype,
+        \ get( g:vsnip_filetypes, l:filetypes.filetype,
+        \ [ l:filetypes.filetype ]
+        \ ) )
+        \ + [ "global" ]
+    endif
+  else
+    let l:filetype = getbufvar( a:bufnr, "&filetype", "" )
+
+    return split( l:filetype, '\.' ) + get( g:vsnip_filetypes, l:filetype, [] ) + [ "global" ]
+  endif
 endfunction
 
 "
@@ -113,4 +132,3 @@ function! vsnip#source#resolve_prefix(prefix) abort
   \   sort(l:prefixes_alias, { a, b -> strlen(b) - strlen(a) })
   \ ]
 endfunction
-
diff --git a/autoload/vsnip/source/user_snippet.vim b/autoload/vsnip/source/user_snippet.vim
index b7e959f..5d6cc64 100644
--- a/autoload/vsnip/source/user_snippet.vim
+++ b/autoload/vsnip/source/user_snippet.vim
@@ -66,4 +66,3 @@ endfun
 fun! vsnip#source#user_snippet#paths(...) abort
   return s:get_source_paths(a:0 ? a:1 : bufnr(''))
 endfun
-
diff --git a/autoload/vsnip/source/vscode.vim b/autoload/vsnip/source/vscode.vim
index e673e41..18e2d53 100644
--- a/autoload/vsnip/source/vscode.vim
+++ b/autoload/vsnip/source/vscode.vim
@@ -101,4 +101,3 @@ function! s:get_language(filetype) abort
   \   'cs': 'csharp',
   \ }, a:filetype, a:filetype)
 endfunction
-
diff --git a/autoload/vsnip/variable.vim b/autoload/vsnip/variable.vim
index 54efd83..8cae2d4 100644
--- a/autoload/vsnip/variable.vim
+++ b/autoload/vsnip/variable.vim
@@ -186,4 +186,3 @@ function! s:VSNIP_CAMELCASE_FILENAME(context) abort
   return substitute(l:basename, '\(\%(\<\l\+\)\%(_\)\@=\)\|_\(\l\)', '\u\1\2', 'g')
 endfunction
 call vsnip#variable#register('VSNIP_CAMELCASE_FILENAME', function('s:VSNIP_CAMELCASE_FILENAME'))
-
diff --git a/doc/vsnip.txt b/doc/vsnip.txt
index 2a65afa..040a405 100644
--- a/doc/vsnip.txt
+++ b/doc/vsnip.txt
@@ -71,6 +71,16 @@ VARIABLE                                                      *vsnip-variable*
       let g:vsnip_filetypes = {}
       let g:vsnip_filetypes.javascriptreact = ['javascript']
 <
+
+    If you are using `treesitter` you can define snippets for injected
+    languages like this:
+
+>
+    let g:vsnip_filetypes['vim/lua'] = ['lua', 'vim/lua']
+    let g:vsnip_filetypes['vue'] = ['html']
+    let g:vsnip_filetypes['vue/javascript'] = ['javascript', 'vue/javascript']
+<
+
  let g:vsnip_deactivate_on = g:vsnip#DeactivateOn.OutsideOfSnippet~
     Specify when to deactivate the current snippet.
 
@@ -107,7 +117,12 @@ FUNCTION                                                      *vsnip-function*
 
     Register your own custom variable resolver.
 
+  vsnip#completefunc()
 
+    Register for finding completions.
+>
+    set complete+=Fvsnip#completefunc
+<
 
 ==============================================================================
 MAPPING                                                        *vsnip-mapping*
diff --git a/lua/vsnip/treesitter.lua b/lua/vsnip/treesitter.lua
new file mode 100644
index 0000000..311be5a
--- /dev/null
+++ b/lua/vsnip/treesitter.lua
@@ -0,0 +1,65 @@
+local M = {}
+
+local ok_parsers, ts_parsers = pcall( require, "nvim-treesitter.parsers" )
+if not ok_parsers then
+  ts_parsers = nil
+end
+
+local ok_utils, ts_utils = pcall( require, "nvim-treesitter.ts_utils" )
+if not ok_utils then
+  ts_utils = nil
+end
+
+local function get_parser_filetype ( lang )
+  if lang and ts_parsers.list[ lang ] then
+    return ts_parsers.list[ lang ].filetype or lang
+  else
+    return ""
+  end
+end
+
+local function is_available ()
+  return ok_parsers and ok_utils
+end
+
+function M.get_ft_at_cursor ( bufnr )
+  local filetypes = {
+    filetype = "",
+    injected_filetype = "",
+  }
+
+  if is_available() then
+    local cur_node = ts_utils.get_node_at_cursor( vim.fn.bufwinid( bufnr ) )
+
+    if cur_node then
+      local parser = ts_parsers.get_parser( bufnr )
+      local language_tree_at_cursor = parser:language_for_range( { cur_node:range() } )
+      local language_at_cursor = language_tree_at_cursor:lang()
+
+      local filetype = get_parser_filetype( language_at_cursor )
+
+      if filetype ~= "" then
+        filetypes.filetype = filetype
+
+        local parent_language_tree = language_tree_at_cursor:parent()
+
+        if parent_language_tree then
+          local parent_language = parent_language_tree:lang()
+          local parent_filetype = get_parser_filetype( parent_language )
+
+          if parent_filetype ~= "" then
+            filetypes.injected_filetype = parent_filetype .. "/" .. filetype
+          end
+        end
+
+        return filetypes
+      end
+    end
+  end
+
+  filetypes.filetype = vim.bo[ bufnr ].filetype or ""
+
+  return filetypes
+end
+
+return M
diff --git a/package.json b/package.json
index f454311..f83d652 100644
--- a/package.json
+++ b/package.json
@@ -2,6 +2,16 @@
   "name": "vim-vsnip",
   "version": "1.0.0",
   "description": "This aims to plugin like Visual Studio Code's Snippet feature.",
+  "homepage": "https://github.com/hrsh7th/vim-test-snips#readme",
+  "bugs": {
+    "url": "https://github.com/hrsh7th/vim-test-snips/issues"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/hrsh7th/vim-test-snips.git"
+  },
+  "license": "MIT",
+  "author": "hrsh7th",
   "scripts": {
     "open": "nvim -u .vimrc",
     "test": "run-s test:*",
@@ -20,18 +30,8 @@
       "pre-commit": "npm run lint && npm run test"
     }
   },
-  "repository": {
-    "type": "git",
-    "url": "git+https://github.com/hrsh7th/vim-test-snips.git"
-  },
-  "author": "hrsh7th",
-  "license": "MIT",
-  "bugs": {
-    "url": "https://github.com/hrsh7th/vim-test-snips/issues"
-  },
-  "homepage": "https://github.com/hrsh7th/vim-test-snips#readme",
   "devDependencies": {
-    "husky": "^3.0.5",
+    "husky": "^9.0.0",
     "npm-run-all": "^4.1.5",
     "watch": "^1.0.2"
   }
diff --git a/plugin/vsnip.vim b/plugin/vsnip.vim
index 2f4f0a7..19e42e6 100644
--- a/plugin/vsnip.vim
+++ b/plugin/vsnip.vim
@@ -222,4 +222,3 @@ endfunction
 function! s:on_buf_write_post() abort
   call vsnip#source#refresh(resolve(fnamemodify(bufname('%'), ':p')))
 endfunction
-
diff --git a/spec/autoload/vsnip.vimspec b/spec/autoload/vsnip.vimspec
index 3d8bc2e..f2da6a4 100644
--- a/spec/autoload/vsnip.vimspec
+++ b/spec/autoload/vsnip.vimspec
@@ -145,5 +145,50 @@ Describe vsnip
 
   End
 
+  Describe #completefunc
+
+    It should return start position
+      enew!
+      set filetype=basic_spec
+      call setline(1, ' if')
+      call cursor([1, 3])
+      call s:expect(vsnip#completefunc(1, '')).to_equal(1)
+    End
+
+    It should return complete items
+      enew!
+      set filetype=basic_spec
+      call s:expect(vsnip#completefunc(0, 'if')[-1]).to_equal({
+      \   'word': 'if',
+      \   'abbr': 'if',
+      \   'kind': 'Snippet',
+      \   'menu': '[v] if',
+      \   'dup': 1,
+      \   'user_data': json_encode({
+      \     'vsnip': {
+      \       'snippet': [
+      \         "if ${1:condition}",
+      \         "\t$0",
+      \         "endif",
+      \       ]
+      \     }
+      \   })
+      \ }, {
+      \   'word': 'inline-fn',
+      \   'abbr': 'inline-fn',
+      \   'kind': 'Snippet',
+      \   'menu': '[v] inline-fn',
+      \   'dup': 1,
+      \   'user_data': json_encode({
+      \     'vsnip': {
+      \       'snippet': [
+      \         "{ -> $1 }$0"
+      \       ]
+      \     }
+      \   })
+      \ })
+    End
+  End
+
 End