We list here some snippets to customize the LSP experience. These are too complex/arbitrary to be enabled by default.

Range Formatting With a Motion

If your language server supports formatting a range of text (as opposed to a whole file), you can use this snippet to map a key to formatting a range with a motion. For example, with this code, gmip in normal mode will format a paragraph.

function format_range_operator()
  local old_func = vim.go.operatorfunc
  _G.op_func_formatting = function()
    local start = vim.api.nvim_buf_get_mark(0, '[')
    local finish = vim.api.nvim_buf_get_mark(0, ']')
    vim.lsp.buf.range_formatting({}, start, finish)
    vim.go.operatorfunc = old_func
    _G.op_func_formatting = nil
  end
  vim.go.operatorfunc = 'v:lua.op_func_formatting'
  vim.api.nvim_feedkeys('g@', 'n', false)
end
vim.api.nvim_set_keymap("n", "gm", "<cmd>lua format_range_operator()<CR>", {noremap = true})

See https://github.com/neovim/neovim/issues/14680 for context.

Peek Definition

To open the target of a textDocument/definition request in a floating window (as in VS Code's "Peek Definition"), you can use the following snippet:

local function preview_location_callback(_, result)
  if result == nil or vim.tbl_isempty(result) then
    return nil
  end
  vim.lsp.util.preview_location(result[1])
end

function PeekDefinition()
  local params = vim.lsp.util.make_position_params()
  return vim.lsp.buf_request(0, 'textDocument/definition', params, preview_location_callback)
end

If the server supports LocationLink, this will show the full target range (e.g., function body) of the definition. Other requests like textDocument/declaration can be "peeked" analogously.

Clangd

SwitchSourceHeader

nvim-lspconfig offers the ClangdSwitchSourceHeader command by default. It simply replaces the current buffer with the corresponding file. If you'd like to open the corresponding file in a new split/vsplit, you can add such commands easily:

local function switch_source_header_splitcmd(bufnr, splitcmd)
  bufnr = require'lspconfig'.util.validate_bufnr(bufnr)
  local clangd_client = require'lspconfig'.util.get_active_client_by_name(bufnr, 'clangd')
  local params = {uri = vim.uri_from_bufnr(bufnr)}
  if clangd_client then
    clangd_client.request("textDocument/switchSourceHeader", params, function(err, result)
      if err then
        error(tostring(err))
      end
      if not result then
        print("Corresponding file can’t be determined")
        return
      end
      vim.api.nvim_command(splitcmd .. " " .. vim.uri_to_fname(result))
    end, bufnr)
  else
    print 'textDocument/switchSourceHeader is not supported by the clangd server active on the current buffer'
  end
end

require'lspconfig'.clangd.setup {

   -----snip------

    commands = {
    	ClangdSwitchSourceHeader = {
    		function() switch_source_header_splitcmd(0, "edit") end;
    		description = "Open source/header in current buffer";
    	},
    	ClangdSwitchSourceHeaderVSplit = {
    		function() switch_source_header_splitcmd(0, "vsplit") end;
    		description = "Open source/header in a new vsplit";
    	},
    	ClangdSwitchSourceHeaderSplit = {
    		function() switch_source_header_splitcmd(0, "split") end;
    		description = "Open source/header in a new split";
    	}
    }
}

The commands ClangdSwitchSourceHeader* are available like normal vim commands, that is:

nnoremap <leader>h :ClangdSwitchSourceHeaderVSplit<CR>

diagnosticls

Auto generated config link

eslint

The following is an example of integrating with eslint, it uses the .eslinrc.js file to identify the project root, and then uses the instance of eslint available in node_modules:

  local util = require "lspconfig".util

  require'lspconfig'.diagnosticls.setup{
    filetypes = {"javascript", "typescript"},
    root_dir = function(fname)
      return util.root_pattern("tsconfig.json")(fname) or
      util.root_pattern(".eslintrc.js")(fname);
    end,
    init_options = {
      linters = {
        eslint = {
          command = "./node_modules/.bin/eslint",
          rootPatterns = {".eslintrc.js", ".git"},
          debounce = 100,
          args = {
            "--stdin",
            "--stdin-filename",
            "%filepath",
            "--format",
            "json"
          },
          sourceName = "eslint",
          parseJson = {
            errorsRoot = "[0].messages",
            line = "line",
            column = "column",
            endLine = "endLine",
            endColumn = "endColumn",
            message = "[eslint] ${message} [${ruleId}]",
            security = "severity"
          },
          securities = {
            [2] = "error",
            [1] = "warning"
          }
        },
      },
      filetypes = {
        javascript = "eslint",
        typescript = "eslint"
      }
    }
  }

EFM

Auto generated config link

eslint

The following is an example of integrating with eslint, it uses the .eslinrc.js file to identify the project root, and then uses the instance of eslint available in node_modules:

  local eslint = {
    lintCommand = "./node_modules/.bin/eslint -f unix --stdin --stdin-filename ${INPUT}",
    lintIgnoreExitCode = true,
    lintStdin = true
  }
  local util = require "lspconfig".util
  
  require "lspconfig".efm.setup {
    --cmd = {"efm-langserver",},
    init_options = {documentFormatting = true},
    filetypes = {"javascript", "typescript"},
    root_dir = function(fname)
      return util.root_pattern("tsconfig.json")(fname) or
      util.root_pattern(".eslintrc.js", ".git")(fname);
    end,
    settings = {
      rootMarkers = {".eslintrc.js", ".git/"},
      languages = {
        typescript = {eslint}
      }
    }
  }

eslint_d

This example uses eslint_d, which is much faster. Read more here

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
}

require "lspconfig".efm.setup {
  init_options = {documentFormatting = true},
  filetypes = {"javascript", "typescript"},
  root_dir = function(fname)
    return util.root_pattern("tsconfig.json")(fname) or
    util.root_pattern(".eslintrc.js", ".git")(fname);
  end,
  settings = {
    rootMarkers = {".eslintrc.js", ".git/"},
    languages = {
      javascript = {eslint},
      typescript = {eslint}
    }
  }
}

Customize LSP CodeLens and Signs

It can be helpful to customize the severity levels that get displayed as a gutter sign and/or codelens virtual text. For example, maybe you want to show everything in the gutter, but only Errors as virtualtext.

-- Set which codelens text levels to show
local original_set_virtual_text = vim.lsp.diagnostic.set_virtual_text
local set_virtual_text_custom = function(diagnostics, bufnr, client_id, sign_ns, opts)
    opts = opts or {}
    -- show all messages that are Warning and above (Warning, Error)
    opts.severity_limit = "Warning"
    original_set_virtual_text(diagnostics, bufnr, client_id, sign_ns, opts)
end

vim.lsp.diagnostic.set_virtual_text = set_virtual_text_custom

Or maybe you want to only show Errors in the gutter,

local orig_set_signs = vim.lsp.diagnostic.set_signs
local set_signs_limited = function(diagnostics, bufnr, client_id, sign_ns, opts)
  opts = opts or {}
  opts.severity_limit = "Error"
  orig_set_signs(diagnostics, bufnr, client_id, sign_ns, opts)
end

vim.lsp.diagnostic.set_signs = set_signs_limited

source

Another configuration that only shows the most severe item in the gutter per line,

-- Capture real implementation of function that sets signs
local orig_set_signs = vim.lsp.diagnostic.set_signs
local set_signs_limited = function(diagnostics, bufnr, client_id, sign_ns, opts)

  -- original func runs some checks, which I think is worth doing
  -- but maybe overkill
  if not diagnostics then
    diagnostics = diagnostic_cache[bufnr][client_id]
  end

  -- early escape
  if not diagnostics then
    return
  end

  -- Work out max severity diagnostic per line
  local max_severity_per_line = {}
  for _,d in pairs(diagnostics) do
    if max_severity_per_line[d.range.start.line] then
      local current_d = max_severity_per_line[d.range.start.line]
      if d.severity < current_d.severity then
        max_severity_per_line[d.range.start.line] = d
      end
    else
      max_severity_per_line[d.range.start.line] = d
    end
  end

  -- map to list
  local filtered_diagnostics = {}
  for i,v in pairs(max_severity_per_line) do
    table.insert(filtered_diagnostics, v)
  end

  -- call original function
  orig_set_signs(filtered_diagnostics, bufnr, client_id, sign_ns, opts)
end
vim.lsp.diagnostic.set_signs = set_signs_limited

source

After neovim 0.7, just need to use vim.diagnostic.config() to set how diagnostics are displayed in virtual text, float, and signs. For example

vim.diagnostic.config({
  virtual_text = {
    source = 'always',
    prefix = '■',
    -- Only show virtual text matching the given severity
    severity = {
      -- Specify a range of severities
      min = vim.diagnostic.severity.ERROR,
    },
  },
  float = {
    source = 'always',
    border = 'rounded',
  },
  signs = true,
  underline = true,
  update_in_insert = false,
  severity_sort = true,
})

jsonls

Use JSON schemas from SchemaStore

The SchemaStore project provides a large collection of JSON schema definitions for many common JSON file types. The SchemaStore.nvim plugin provides access to the SchemaStore catalog as a Lua library that can be used to configure jsonls.

To use the entire SchemaStore catalog with jsonls, install the SchemaStore.nvim plugin, then update your lspconfig jsonls settings:

To use SchemaStore.nvim with lspconfig + jsonls:

require('lspconfig').jsonls.setup {
  settings = {
    json = {
      schemas = require('schemastore').json.schemas(),
      validate = { enable = true },
    },
  },
}

For an explanation of why the validate = { enable = true } option is recommended, see SchemaStore.nvim#8.

To use a subset of the catalog, you can select schemas by name (see the catalog for a full list):

require('lspconfig').jsonls.setup {
  settings = {
    json = {
      schemas = require('schemastore').json.schemas {
        select = {
          '.eslintrc',
          'package.json',
        },
      },
      validate = { enable = true },
    },
  },
}

To ignore certain schemas from the catalog:

require('lspconfig').jsonls.setup {
  settings = {
    json = {
      schemas = require('schemastore').json.schemas {
        ignore = {
          '.eslintrc',
          'package.json',
        },
      },
      validate = { enable = true },
    },
  },
}

To replace certain schemas from the catalog with your own:

require('lspconfig').jsonls.setup {
  settings = {
    json = {
      schemas = require('schemastore').json.schemas {
        replace = {
          ['package.json'] = {
            description = 'package.json overriden',
            fileMatch = { 'package.json' },
            name = 'package.json',
            url = 'https://example.com/package.json',
          },
        },
      },
      validate = { enable = true },
    },
  },
}

If you want to use your own schemas in addition to schemas from SchemaStore, you can merge them:

require('lspconfig').jsonls.setup {
  settings = {
    json = {
      schemas = vim.list_extend(
        {
          {
            description = 'My Custom JSON schema',
            fileMatch = { 'foobar.json', '.foobar.json' },
            name = 'foobar.json',
            url = 'https://example.com/schema/foobar.json',
          },
        },
        require('schemastore').json.schemas {
          select = {
            '.eslintrc',
            'package.json',
          },
        }
      ),
      validate = { enable = true },
    },
  },
}

ltex-ls

To add the user dictionary from the built-in Neovim spell checker to ltex-ls, add the following to your LSP setup:

-- ===========================================
--  Add user dictionary for ltex-ls
--  * en.utf-8.add must be created using `zg`
-- ===========================================
local path = vim.fn.stdpath 'config' .. '/spell/en.utf-8.add'
local words = {}

for word in io.open(path, 'r'):lines() do
  table.insert(words, word)
end

nvim_lsp.ltex.setup {
  on_attach = on_attach,
  settings = {
    ltex = {
      dictionary = {
        ['en-US'] = words,
      },
    },
  },
}

The changes take places when you reload the config.

Use nvim-notify to display LSP messages

The nvim-notify plugin can be used to display messages received from the LSP server.

vim.lsp.handlers['window/showMessage'] = function(_, result, ctx)
  local client = vim.lsp.get_client_by_id(ctx.client_id)
  local lvl = ({ 'ERROR', 'WARN', 'INFO', 'DEBUG' })[result.type]
  notify(result.message, lvl, {
    title = 'LSP | ' .. client.name,
    timeout = 10000,
    keep = function()
      return lvl == 'ERROR' or lvl == 'WARN'
    end,
  })
end

User contributed tips - neovim/nvim-lspconfig GitHub Wiki

Range Formatting With a Motion

Peek Definition

Clangd

SwitchSourceHeader

diagnosticls

eslint

EFM

eslint

eslint_d

Customize LSP CodeLens and Signs

jsonls

Use JSON schemas from SchemaStore

ltex-ls

Use nvim-notify to display LSP messages

⚠️ GitHub.com Fallback ⚠️

User contributed tips - neovim/nvim-lspconfig GitHub Wiki

Range Formatting With a Motion

Peek Definition

Clangd

SwitchSourceHeader

diagnosticls

eslint

EFM

eslint

eslint_d

Customize LSP CodeLens and Signs

jsonls

Use JSON schemas from SchemaStore

ltex-ls

Use nvim-notify to display LSP messages

⚠️ **GitHub.com Fallback** ⚠️

⚠️ GitHub.com Fallback ⚠️