Key note categories and examples for tech issues

Try Neovim native LSP

This is an example note

I took this note when I first tried the native LSP support on Neovim 0.5 back in 2021.


Though neovim embeds tree-sitter, it is not out-of-box for users. We need this to install the languages.


Plug 'nvim-treesitter/nvim-treesitter', {'do': ':TSUpdate'}
Plug 'nvim-treesitter/playground'

For Dein.nvim:

repo = "nvim-treesitter/nvim-treesitter"
hook_post_update = 'TSUpdate'
hook_source = '''
source ~/.config/nvim/plugins/treesitter.rc.vim

repo = "nvim-treesitter/playground"

And :TSInstall [language] to install a language parser. Sometimes, you may not notice what tree-sitter does. Just try :TSPlaygroudToggle, you will have a clearer understanding of tree-sitter.


It is similar to nvim-treesitter but for LSP client, which is needed for install and communicate with language servers of each language.


Plug 'neovim/nvim-lspconfig'
repo = "neovim/nvim-lspconfig"
on_lua = 'lspconfig'
hook_add = """
source ~/.config/nvim/plugins/lspconfig.rc.vim

The language servers are needed to install externally on system level with any package manager you like. I use Homebrew, go get and npm/yarn all together. Follow for details of each language server.

Take Go and gopls as example:

Install gopls:

GO111MODULE=on go get

Then setup with lspconfig:


When you open a file, :LspInfo to know whether a LSP client is attached.

Use flow

nvim-treesitter/nvim-treesitter: Nvim Treesitter configurations and abstraction layer

lua <<EOF
local parser_config = require "nvim-treesitter.parsers".get_parser_configs()
parser_config.typescript.used_by = "javascriptflow"

Update toml:

repo = "nvim-treesitter/nvim-treesitter"
hook_post_update = """
hook_post_source = """
source ~/.config/nvim/plugins/treesitter.rc.vim


  Default Values:
    cmd = { "npx", "--no-install", "flow", "lsp" }
    filetypes = { "javascript", "javascriptreact", "javascript.jsx" }
    root_dir = root_pattern(".flowconfig")

Inserted it into .config/nvim/plugins/lspconfig.rc.vim:

lua << EOF
local nvim_lsp = require('lspconfig')

-- Use an on_attach function to only map the following keys
-- after the language server attaches to the current buffer
local on_attach = function(client, bufnr)
  local function buf_set_keymap(...) vim.api.nvim_buf_set_keymap(bufnr, ...) end
  local function buf_set_option(...) vim.api.nvim_buf_set_option(bufnr, ...) end

  --Enable completion triggered by <c-x><c-o>
  buf_set_option('omnifunc', 'v:lua.vim.lsp.omnifunc')

  -- Mappings.
  local opts = { noremap=true, silent=true }

  -- See `:help vim.lsp.*` for documentation on any of the below functions
  buf_set_keymap('n', 'gD', '<Cmd>lua vim.lsp.buf.declaration()<CR>', opts)
  buf_set_keymap('n', 'gd', '<Cmd>lua vim.lsp.buf.definition()<CR>', opts)
  buf_set_keymap('n', 'K', '<Cmd>lua vim.lsp.buf.hover()<CR>', opts)
  buf_set_keymap('n', 'gi', '<cmd>lua vim.lsp.buf.implementation()<CR>', opts)
  buf_set_keymap('n', '<C-k>', '<cmd>lua vim.lsp.buf.signature_help()<CR>', opts)
  buf_set_keymap('n', '<space>wa', '<cmd>lua vim.lsp.buf.add_workspace_folder()<CR>', opts)
  buf_set_keymap('n', '<space>wr', '<cmd>lua vim.lsp.buf.remove_workspace_folder()<CR>', opts)
  buf_set_keymap('n', '<space>wl', '<cmd>lua print(vim.inspect(vim.lsp.buf.list_workspace_folders()))<CR>', opts)
  buf_set_keymap('n', '<space>D', '<cmd>lua vim.lsp.buf.type_definition()<CR>', opts)
  buf_set_keymap('n', '<space>rn', '<cmd>lua vim.lsp.buf.rename()<CR>', opts)
  buf_set_keymap('n', '<space>ca', '<cmd>lua vim.lsp.buf.code_action()<CR>', opts)
  buf_set_keymap('n', 'gr', '<cmd>lua vim.lsp.buf.references()<CR>', opts)
  buf_set_keymap('n', '<space>e', '<cmd>lua vim.lsp.diagnostic.show_line_diagnostics()<CR>', opts)
  buf_set_keymap('n', '[d', '<cmd>lua vim.lsp.diagnostic.goto_prev()<CR>', opts)
  buf_set_keymap('n', ']d', '<cmd>lua vim.lsp.diagnostic.goto_next()<CR>', opts)
  buf_set_keymap('n', '<space>q', '<cmd>lua vim.lsp.diagnostic.set_loclist()<CR>', opts)
  buf_set_keymap("n", "<space>f", "<cmd>lua vim.lsp.buf.formatting()<CR>", opts)


-- Use a loop to conveniently call 'setup' on multiple servers and
-- map buffer local keybindings when the language server attaches
local servers = { "pyright", "rust_analyzer", "tsserver" }
for _, lsp in ipairs(servers) do
  nvim_lsp[lsp].setup { on_attach = on_attach }

lua << EOF
  Default Values:
    cmd = { "npx", "--no-install", "flow", "lsp" }
    filetypes = { "javascript", "javascriptreact", "javascript.jsx" }
    root_dir = root_pattern(".flowconfig")

But keymapping is not working? Or, maybe flow is not working.

Failed to load lspconfig:

[dein] Error occurred while executing hook: nvim-lspconfig
[dein] Vim(lua):E5108: Error executing lua [string ":lua"]:1: module 'lspconfig' not found:
[dein] ^Ino field package.preload['lspconfig']
[dein] ^Ino file './lspconfig.lua'
[dein] ^Ino file '/opt/homebrew/Cellar/luajit/HEAD-1e66d0f/share/luajit-2.1.0-beta3/lspconfig.lua'
[dein] ^Ino file '/usr/local/share/lua/5.1/lspconfig.lua'
[dein] ^Ino file '/usr/local/share/lua/5.1/lspconfig/init.lua'
[dein] ^Ino file '/opt/homebrew/Cellar/luajit/HEAD-1e66d0f/share/lua/5.1/lspconfig.lua'
[dein] ^Ino file '/opt/homebrew/Cellar/luajit/HEAD-1e66d0f/share/lua/5.1/lspconfig/init.lua'
[dein] ^Ino file './'
[dein] ^Ino file '/usr/local/lib/lua/5.1/'
[dein] ^Ino file '/opt/homebrew/Cellar/luajit/HEAD-1e66d0f/lib/lua/5.1/'
[dein] ^Ino file '/usr/local/lib/lua/5.1/'

Copied files manually. Got this error:

E5108: Error executing lua ...ache/dein/.cache/init.vim/.dein/lua/lspconfig/_lspui.lua:105: Invalid key 'border'

Update packages:

brew install --HEAD tree-sitter
brew upgrade --fetch-HEAD luajit
brew upgrade --fetch-HEAD neovim

Okay, that worked.

[dein] Error occurred while executing hook: nvim-lspconfig
[dein] Vim(lua):E5107: Error loading lua [string ":lua"]:3: function arguments expected near 'Values'

The below lines are not necessary:

  Default Values:

Had to add a language:

local servers = { "flow", "pyright", "rust_analyzer", "tsserver" }
for _, lsp in ipairs(servers) do
  nvim_lsp[lsp].setup { on_attach = on_attach }

Treesitter error

nvim-treesitter[haskell]: Error during compilation
src/ error: expected expression
  return [=](A a) { return f(g(a)); };
src/ error: expected expression
  return [=](A a) { return f(g(a)); };

Could you try adding the -std=c++11 flag here: This could cause problems compiling the C code...

brew install gcc

Parser config:

  tsx = {
    filetype = "typescriptreact",
    install_info = {
      files = { "src/parser.c", "src/scanner.c" },
      generate_requires_npm = true,
      location = "tree-sitter-tsx/tsx",
      url = ""
    maintainers = { "@steelsojka" },
    used_by = "javascript",
    <metatable> = {
      __newindex = <function 59>

  typescript = {
    install_info = {
      files = { "src/parser.c", "src/scanner.c" },
      generate_requires_npm = true,
      location = "tree-sitter-typescript/typescript",
      url = ""
    maintainers = { "@steelsojka" },
    <metatable> = {
      __newindex = <function 61>
lua <<EOF
local parser_config = require "nvim-treesitter.parsers".get_parser_configs()
print("config:", vim.inspect(parser_config))

It worked:

set filetype=typescriptreact

But it's not ideal because it detects as TypeScript but actually it's Flow.

Editing lua/nvim-treesitter/parsers.lua directly worked. Reported it: parser_config.tsx.used_by is not working · Issue #161 · tree-sitter/tree-sitter-typescript

Use eslint

npm i -g diagnostic-languageserver prettier-eslint-cli


brew install markdownlint-cli

I don't need it.


Looks nice!


Format on save

it blocks while formatting and is slow:

vim.cmd [[ autocmd BufWritePre <buffer> lua vim.lsp.buf.formatting_sync() ]]
-- formatting
vim.lsp.handlers["textDocument/formatting"] = function(err, _, result, _, bufnr)
    if err ~= nil or result == nil then
    if not vim.api.nvim_buf_get_option(bufnr, "modified") then
        local view = vim.fn.winsaveview()
        vim.lsp.util.apply_text_edits(result, bufnr)
        if bufnr == nil or bufnr == vim.api.nvim_get_current_buf() then
            vim.api.nvim_command("noautocmd :update")

local on_attach = function(client, bufnr)

  if client.resolved_capabilities.document_formatting then
    vim.api.nvim_command [[augroup Format]]
    vim.api.nvim_command [[autocmd! * <buffer>]]
    vim.api.nvim_command [[autocmd BufWritePost <buffer> lua vim.lsp.buf.formatting()]]
    vim.api.nvim_command [[augroup END]]

Icon and color

-- color and icons

vim.lsp.handlers["textDocument/publishDiagnostics"] = vim.lsp.with(
  vim.lsp.diagnostic.on_publish_diagnostics, {
    underline = true,
    -- This sets the spacing and the prefix, obviously.
    virtual_text = {
      spacing = 4,
      prefix = '‚úò'


nnoremap <silent> <C-j> :Lspsaga diagnostic_jump_next<CR>


It won't work:

highlight LspDiagnosticsDefaultError guifg=BrightRed
highlight LspDiagnosticsVirtualTextError guifg=Red ctermfg=Red
highlight LspDiagnosticsDefaultWarning guifg=BrightYellow
highlight LspDiagnosticsVirtualTextWarning guifg=Yellow ctermfg=Yellow

I keep getting these errors:

[dein] Error occurred while executing hook: lspsaga.nvim
[dein] Vim(lua):E5108: Error executing lua Vim(call):E714: List required
[dein] Error occurred while executing hook: lsp-colors.nvim
[dein] Vim(lua):E5108: Error executing lua Vim(call):E714: List required


Use nvim-compe.

Customize icons:

local protocol = require'vim.lsp.protocol'
protocol.CompletionItemKind = {
  'Óòí', -- Text
  '\u{f09a}', -- Method
  '\u{0192}', -- Function
  '\u{0192}', -- Constructor
  'Óûõ', -- Field
  'Óûõ', -- Variable
  'ÔÉ®', -- Class
  '\u{f417}', -- Interface
  '\u{f40d}', -- Module
  'Óò§', -- Property
  'Ôëµ', -- Unit
  '\u{f89f}', -- Value
  '\u{f435}', -- Enum
  '\u{f1de}', -- Keyword
  '\u{e60b}', -- Snippet
  'Óà´', -- Color
  'ÔÖõ', -- File
  '\u{fa46}', -- Reference
  'ÔÑï', -- Folder
  'ÔÖù', -- EnumMember
  '\u{f8fe}', -- Constant
  'ÔÉä', -- Struct
  'ÔÉß', -- Event
  'ﬦ', -- Operator
  'Óòé', -- TypeParameter

fuzzy finder - telescope.nvim


nnoremap <silent> ;f <cmd>Telescope find_files<cr>
nnoremap <silent> ;r <cmd>Telescope live_grep<cr>
nnoremap <silent> ;b <cmd>Telescope buffers<cr>
nnoremap <silent> ;; <cmd>Telescope help_tags<cr>

lua << EOF
local actions = require('telescope.actions')
-- Global remapping
  defaults = {
    mappings = {
      n = {
        ["q"] = actions.close


Switch from Dein to VimPlug

dein.vim is quite unstable. tired of using it.


sh -c 'curl -fLo $HOME/.local/share/nvim/site/autoload/plug.vim --create-dirs \'

The directory for plugins is ~/.local/share/nvim/plugged:

call plug#begin(stdpath('data') . '/plugged')

Plug 'tpope/vim-rhubarb'

call plug#end()

lexima won't work with completion


oh, completion also supports auto-paren? This solved:

let g:completion_confirm_key = ""
imap <expr> <cr>  pumvisible() ? complete_info()["selected"] != "-1" ?
                 \ "\<Plug>(completion_confirm_completion)"  : "\<c-e>\<CR>" :  "\<CR>"

But, when nvim-treesitter is enabled, it won't work properly. Why? Setting indent.enable = false in nvim-treesitter.configs solved!

require'nvim-treesitter.configs'.setup {
  indent = {
    enable = false,
    disable = {},

Try lua based statusline plugin

Works great!

Screen Shot 2021-06-18 at 19.44.25.png

Customize tabline


Since the number of tab labels will vary, you need to use an expression for
the whole option.  Something like:
	:set tabline=%!MyTabLine()

Then define the MyTabLine() function to list all the tab pages labels.  A
convenient method is to split it in two parts:  First go over all the tab
pages and define labels for them.  Then get the label for each tab page.

	function MyTabLine()
	  let s = ''
	  for i in range(tabpagenr('$'))
	    " select the highlighting
	    if i + 1 == tabpagenr()
	      let s .= '%#TabLineSel#'
	      let s .= '%#TabLine#'

	    " set the tab page number (for mouse clicks)
	    let s .= '%' . (i + 1) . 'T'

	    " the label is made by MyTabLabel()
	    let s .= ' %{MyTabLabel(' . (i + 1) . ')} '

	  " after the last tab fill with TabLineFill and reset tab page nr
	  let s .= '%#TabLineFill#%T'

	  " right-align the label to close the current tab page
	  if tabpagenr('$') > 1
	    let s .= '%=%#TabLine#%999Xclose'

	  return s

Now the MyTabLabel() function is called for each tab page to get its label.

	function MyTabLabel(n)
	  let buflist = tabpagebuflist(a:n)
	  let winnr = tabpagewinnr(a:n)
	  return bufname(buflist[winnr - 1])

Lightline's tabline:

Created my tabline settings: .dotfiles/.config/nvim/after/plugin/tabline.rc.vim

WSL (Windows)

This would be another story..

Use eslint_d

eslint-prettier is outdated. It doesn't support TypeScript 4.0.

local lspconfig = require"lspconfig"

local eslint = {
  lintCommand = "eslint_d -f unix --stdin --stdin-filename ${INPUT}",
  lintStdin = true,
  lintFormats = {"%f:%l:%c: %m"},
  lintIgnoreExitCode = true,
  formatCommand = "eslint_d --fix-to-stdout --stdin --stdin-filename=${INPUT}",
  formatStdin = true

lspconfig.tsserver.setup {
  on_attach = function(client)
    if client.config.flags then
      client.config.flags.allow_incremental_sync = true
    client.resolved_capabilities.document_formatting = false

lspconfig.efm.setup {
  on_attach = function(client)
    client.resolved_capabilities.document_formatting = true
    client.resolved_capabilities.goto_definition = false
  root_dir = function()
    if not eslint_config_exists() then
      return nil
    return vim.fn.getcwd()
  settings = {
    languages = {
      javascript = {eslint},
      javascriptreact = {eslint},
      ["javascript.jsx"] = {eslint},
      typescript = {eslint},
      ["typescript.tsx"] = {eslint},
      typescriptreact = {eslint}
  filetypes = {


npm install -g eslint_d

Okay, it works!

    formatters = {
      eslint_d = {
        command = 'eslint_d',
        args = { '--stdin', '--stdin-filename', '%filename', '--fix-to-stdout' },
        rootPatterns = { '.git' },

signature help is not working


No, it's working.

Annoying prompts

When saving .tsx file, it prompts:

Select a language server:
(1) diagnosticls, (2) tsserver:

This is from here:

That's annoying.

Use formatting_seq_sync

vim.api.nvim_command [[autocmd BufWritePre <buffer> lua vim.lsp.buf.formatting_seq_sync()]]

Since eslint_d is enough fast, I can remove vim.lsp.handlers["textDocument/formatting"] handler.

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