return {
  {
    'neovim/nvim-lspconfig', -- LSP
    config = function()
      --vim.lsp.set_log_level("debug")

      local status, nvim_lsp = pcall(require, "lspconfig")
      if (not status) then return end

      local protocol = require('vim.lsp.protocol')

      -- 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', 'gi', '<cmd>lua vim.lsp.buf.implementation()<CR>', opts)
        buf_set_keymap('n', 'K', '<Cmd>lua vim.lsp.buf.hover()<CR>', opts)
        buf_set_keymap('n', 'gr', '<cmd>lua vim.lsp.buf.references()<CR>', opts)
        --buf_set_keymap('n', 'K', '<Cmd>lua vim.lsp.buf.hover()<CR>', opts)
      end

      protocol.CompletionItemKind = {
        '', -- Text
        '', -- Method
        '', -- Function
        '', -- Constructor
        '', -- Field
        '', -- Variable
        '', -- Class
        'ﰮ', -- Interface
        '', -- Module
        '', -- Property
        '', -- Unit
        '', -- Value
        '', -- Enum
        '', -- Keyword
        '﬌', -- Snippet
        '', -- Color
        '', -- File
        '', -- Reference
        '', -- Folder
        '', -- EnumMember
        '', -- Constant
        '', -- Struct
        '', -- Event
        'ﬦ', -- Operator
        '', -- TypeParameter
      }

      -- Set up completion using nvim_cmp with LSP source
      local capabilities = require('cmp_nvim_lsp').default_capabilities(
        vim.lsp.protocol.make_client_capabilities()
      )

      nvim_lsp.flow.setup {
        on_attach = on_attach,
        capabilities = capabilities
      }

      -- nvim_lsp.solargraph.setup {}

      nvim_lsp.ts_ls.setup {
        on_attach = on_attach,
        filetypes = { "typescript", "typescriptreact", "typescript.tsx", "javascript", "vue" },
        cmd = { "typescript-language-server", "--stdio" },
        capabilities = capabilities
      }

      nvim_lsp.sourcekit.setup {
        on_attach = on_attach,
      }

      nvim_lsp.lua_ls.setup {
        on_attach = on_attach,
        settings = {
          Lua = {
            diagnostics = {
              -- Get the language server to recognize the `vim` global
              globals = { 'vim' },
            },

            workspace = {
              -- Make the server aware of Neovim runtime files
              library = vim.api.nvim_get_runtime_file("", true),
              checkThirdParty = false
            },
          },
        },
      }

      vim.lsp.handlers["textDocument/publishDiagnostics"] = vim.lsp.with(
        vim.lsp.diagnostic.on_publish_diagnostics, {
        underline = true,
        update_in_insert = false,
        virtual_text = { spacing = 4, prefix = "●" },
        severity_sort = true,
      }
      )

      -- Diagnostic symbols in the sign column (gutter)
      local signs = { Error = " ", Warn = " ", Hint = " ", Info = " " }
      for type, icon in pairs(signs) do
        local hl = "DiagnosticSign" .. type
        vim.fn.sign_define(hl, { text = icon, texthl = hl, numhl = "" })
      end

      vim.diagnostic.config({
        virtual_text = {
          prefix = '●'
        },
        update_in_insert = true,
        float = {
          source = "always", -- Or "if_many"
        },
      })

      _timers = {}
      local function setup_diagnostics(client, buffer)
        if require("vim.lsp.diagnostic")._enable then
          return
        end

        local diagnostic_handler = function()
          local params = vim.lsp.util.make_text_document_params(buffer)
          client.request("textDocument/diagnostic", { textDocument = params }, function(err, result)
            if err then
              local err_msg = string.format("diagnostics error - %s", vim.inspect(err))
              vim.lsp.log.error(err_msg)
            end
            local diagnostic_items = {}
            if result then
              diagnostic_items = result.items
            end
            vim.lsp.diagnostic.on_publish_diagnostics(
              nil,
              vim.tbl_extend("keep", params, { diagnostics = diagnostic_items }),
              { client_id = client.id }
            )
          end)
        end

        diagnostic_handler() -- to request diagnostics on buffer when first attaching

        vim.api.nvim_buf_attach(buffer, false, {
          on_lines = function()
            if _timers[buffer] then
              vim.fn.timer_stop(_timers[buffer])
            end
            _timers[buffer] = vim.fn.timer_start(200, diagnostic_handler)
          end,
          on_detach = function()
            if _timers[buffer] then
              vim.fn.timer_stop(_timers[buffer])
            end
          end,
        })
      end

      require("lspconfig").ruby_lsp.setup({
        on_attach = function(client, buffer)
          setup_diagnostics(client, buffer)
        end,
      })
    end
  },
  {
    'onsails/lspkind-nvim', -- vscode-like pictograms
    config = function()
      require('lspkind').init({
        mode = 'symbol',
        preset = 'codicons',
        -- override preset symbols
        --
        -- default: {}
        symbol_map = {
        Text = "",
        Method = "",
        Function = "",
        Constructor = "",
        Field = "ﰠ",
        Variable = "",
        Class = "ﴯ",
        Interface = "",
        Module = "",
        Property = "ﰠ",
        Unit = "塞",
        Value = "",
        Enum = "",
        Keyword = "",
        Snippet = "",
        Color = "",
        File = "",
        Reference = "",
        Folder = "",
        EnumMember = "",
        Constant = "",
        Struct = "פּ",
        Event = "",
        Operator = "",
        TypeParameter = ""
        },
      })
    end
  },
  'jose-elias-alvarez/null-ls.nvim', -- inject LSP diagnostics, code actions
  {
    'glepnir/lspsaga.nvim', -- LSP UIs
    config = function()
      local opts = { noremap = true, silent = true }
      vim.keymap.set('n', '<C-j>', '<Cmd>Lspsaga diagnostic_jump_next<CR>', opts)
      vim.keymap.set('n', 'K', '<Cmd>Lspsaga hover_doc<CR>', opts)
      -- vim.keymap.set('n', 'gd', '<Cmd>Lspsaga lsp_finder<CR>', opts)
      vim.keymap.set('i', '<C-k>', '<Cmd>Lspsaga signature_help<CR>', opts)
      vim.keymap.set('n', 'gp', '<Cmd>Lspsaga preview_definition<CR>', opts)
      vim.keymap.set('n', 'gr', '<Cmd>Lspsaga rename<CR>', opts)
    end
  },
  'folke/trouble.nvim', -- better diagnostics
}