nvim_config/lua/config/lspconfig.lua

local nvim_lsp = require('lspconfig')

local on_attach = function(client, bufrn)
    Mapper = require("nvim-mapper")
    local function buf_set_keymap(...) Mapper.map_buf(bufrn, ...) end
    local function buf_set_option(...) vim.api.nvim_buf_set_option(bufrn, ...) end

    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, "LSP", "declaration", "Go to declaration")
  buf_set_keymap('n', 'gd', '<cmd>lua vim.lsp.buf.definition()<CR>', opts, "LSP", "definition", "Go to definition")
  buf_set_keymap('n', 'K', '<cmd>lua vim.lsp.buf.hover()<CR>', opts, "LSP", "hover", "Hover")
  buf_set_keymap('n', 'gi', '<cmd>lua vim.lsp.buf.implementation()<CR>', opts, "LSP", "implementation", "Go to implementation")
  buf_set_keymap('n', '<C-k>', '<cmd>lua vim.lsp.buf.signature_help()<CR>', opts, "LSP", "signature_help", "Show signature help")
  buf_set_keymap('n', '<space>wa', '<cmd>lua vim.lsp.buf.add_workspace_folder()<CR>', opts, "LSP", "add_workspace_folder", "Add workspace folder")
  buf_set_keymap('n', '<space>wr', '<cmd>lua vim.lsp.buf.remove_workspace_folder()<CR>', opts, "LSP", "remove_workspace_folder", "Remove workspace folder")
  buf_set_keymap('n', '<space>wl', '<cmd>lua print(vim.inspect(vim.lsp.buf.list_workspace_folders()))<CR>', opts, "LSP", "list_workspace_folders", "List workspace folder")
  buf_set_keymap('n', '<space>D', '<cmd>lua vim.lsp.buf.type_definition()<CR>', opts, "LSP", "type_definition", "Show type definition")
  buf_set_keymap('n', '<space>rn', '<cmd>lua vim.lsp.buf.rename()<CR>', opts, "LSP", "rename", "Rename")
  buf_set_keymap('n', '<space>ca', '<cmd>lua vim.lsp.buf.code_action()<CR>', opts, "LSP", "code_action", "Show code actions")
  buf_set_keymap('n', 'gr', '<cmd>lua vim.lsp.buf.references()<CR>', opts, "LSP", "references", "Show references")
  buf_set_keymap('n', '<space>e', '<cmd>lua vim.lsp.diagnostic.show_line_diagnostics()<CR>', opts, "LSP", "show_line_diagnostics", "Show line diagnostic")
  buf_set_keymap('n', '[d', '<cmd>lua vim.lsp.diagnostic.goto_prev()<CR>', opts, "LSP", "goto_prev", "Go to previous")
  buf_set_keymap('n', ']d', '<cmd>lua vim.lsp.diagnostic.goto_next()<CR>', opts, "LSP", "goto_next", "Go to next")
  buf_set_keymap('n', '<space>q', '<cmd>lua vim.lsp.diagnostic.set_loclist()<CR>', opts, "LSP", "set_loclist", "Set loclist")
  buf_set_keymap('n', '<space>f', '<cmd>lua vim.lsp.buf.formatting()<CR>', opts, "LSP", "formatting", "Format")
end

-- Launch language servers
local servers = { 'pyright', 'pylsp', 'gopls', 'rust_analyzer', 'tsserver', 'elixirls', 'dartls', 'denols', 'clangd', 'zls' }
for _, lsp in ipairs(servers) do
  nvim_lsp[lsp].setup {
    on_attach = on_attach,
    flags = {
      debounce_text_changes = 150,
    }
  }
end

local capabilities = vim.lsp.protocol.make_client_capabilities()
capabilities.textDocument.completion.completionItem.snippetSupport = true

require'lspconfig'.jsonls.setup {
  cmd = { "vscode-json-languageserver", "--stdio" },
  capabilities = capabilities,
  commands = {
  Format = {
      function()
        vim.lsp.buf.range_formatting({},{0,0},{vim.fn.line("$"),0})
      end
    },
  },
}

-- Format on save
vim.cmd [[autocmd BufWritePre <buffer> lua vim.lsp.buf.formatting_sync()]]