Custom Neovim Statusline

1. Introduction
2. Prerequisites
3. Statusline Modules
4. Building the Statusline
5. Showing the Statusline
6. Bonus modules
- 6.1. Git Info
7. More Resources

1. Introduction

The statusline is an integral part of (neo)vim's interface. I'd always fancied making my own statusline, and galaxyline becoming unmaintained pushed me to make the switch.
This is what it looks like right now:

2. Prerequisites

Neovim 0.6 or above (0.5 might work too, but I can't guarantee it)
A Nerd Font

…and that's it.

Let's get started.

3. Statusline Modules

We define each module individually, and then build the statusline at the end. It's more manageable this way.

3.1. Mode Indicator

The code below creates a table that defines the string name (which will be displayed in the statusline) for each output of vim.api.nvim_get_mode().mode.

local modes = {
  ["n"] = "NORMAL",
  ["no"] = "NORMAL",
  ["v"] = "VISUAL",
  ["V"] = "VISUAL LINE",
  [""] = "VISUAL BLOCK",
  ["s"] = "SELECT",
  ["S"] = "SELECT LINE",
  [""] = "SELECT BLOCK",
  ["i"] = "INSERT",
  ["ic"] = "INSERT",
  ["R"] = "REPLACE",
  ["Rv"] = "VISUAL REPLACE",
  ["c"] = "COMMAND",
  ["cv"] = "VIM EX",
  ["ce"] = "EX",
  ["r"] = "PROMPT",
  ["rm"] = "MOAR",
  ["r?"] = "CONFIRM",
  ["!"] = "SHELL",
  ["t"] = "TERMINAL",
}

Now, to actually get the mode and match it with modes:

local function mode()
  local current_mode = vim.api.nvim_get_mode().mode
  return string.format(" %s ", modes[current_mode]):upper()
end

I'd like to have different colors for different modes. The function below returns the color for the current mode. I have set these highlights in another part of my configuration, for each theme.
If you don't want different colors for each mode, simply remove this function and remove all occurences of it below. Everything should still work.

local function update_mode_colors()
  local current_mode = vim.api.nvim_get_mode().mode
  local mode_color = "%#StatusLineAccent#"
  if current_mode == "n" then
      mode_color = "%#StatuslineAccent#"
  elseif current_mode == "i" or current_mode == "ic" then
      mode_color = "%#StatuslineInsertAccent#"
  elseif current_mode == "v" or current_mode == "V" or current_mode == "" then
      mode_color = "%#StatuslineVisualAccent#"
  elseif current_mode == "R" then
      mode_color = "%#StatuslineReplaceAccent#"
  elseif current_mode == "c" then
      mode_color = "%#StatuslineCmdLineAccent#"
  elseif current_mode == "t" then
      mode_color = "%#StatuslineTerminalAccent#"
  end
  return mode_color
end

3.2. File

What is a statusline without the filename?

Here, we use a few modifiers with vim.fn.fnamemodify to customize what the filepath looks like:

:~ - reduces filename to be relative to the home directory, i.e. replace /home/<user> with ~.
:. - reduces filename to be relative to the current directory.
:h - reduces filename to only the head (without this it would be printed twice.)

Refer to :h filename-modifiers for more.

local function filepath()
  local fpath = vim.fn.fnamemodify(vim.fn.expand "%", ":~:.:h")
  if fpath == "" or fpath == "." then
      return " "
  end

  return string.format(" %%<%s/", fpath)
end

Here, ~ refers to the current file name, and :t modifies it to only show the tail part

local function filename()
  local fname = vim.fn.expand "%:t"
  if fname == "" then
      return ""
  end
  return fname .. " "
end

3.3. LSP

LSP is cool.

The function below returns the icon and count for each level if the count is not zero. i.e. the statusline doesnt show the number of errors (or warnings, info and hints) if there aren't any.

local function lsp()
  local count = {}
  local levels = {
    errors = "Error",
    warnings = "Warn",
    info = "Info",
    hints = "Hint",
  }

  for k, level in pairs(levels) do
    count[k] = vim.tbl_count(vim.diagnostic.get(0, { severity = level }))
  end

  local errors = ""
  local warnings = ""
  local hints = ""
  local info = ""

  if count["errors"] ~= 0 then
    errors = " %#LspDiagnosticsSignError# " .. count["errors"]
  end
  if count["warnings"] ~= 0 then
    warnings = " %#LspDiagnosticsSignWarning# " .. count["warnings"]
  end
  if count["hints"] ~= 0 then
    hints = " %#LspDiagnosticsSignHint# " .. count["hints"]
  end
  if count["info"] ~= 0 then
    info = " %#LspDiagnosticsSignInformation# " .. count["info"]
  end

  return errors .. warnings .. hints .. info .. "%#Normal#"
end

3.4. Filetype

Takes the filetype and makes it uppercase

local function filetype()
  return string.format(" %s ", vim.bo.filetype):upper()
end

3.5. Line Info

%P - Percentage through the file.
%l - Line Number
%c - Column Number

local function lineinfo()
  if vim.bo.filetype == "alpha" then
    return ""
  end
  return " %P %l:%c "
end

4. Building the Statusline

Let us build the statusline using the modules defined above. Here, we take a table of strings (returned by the functions above), and concatenate them into one string (which is what the statusline wil be set to.)

Statusline = {}

Statusline.active = function()
  return table.concat {
    "%#Statusline#",
    update_mode_colors(),
    mode(),
    "%#Normal# ",
    filepath(),
    filename(),
    "%#Normal#",
    lsp(),
    "%=%#StatusLineExtra#",
    filetype(),
    lineinfo(),
  }
end

function Statusline.inactive()
  return " %F"
end

function Statusline.short()
  return "%#StatusLineNC#   NvimTree"
end

5. Showing the Statusline

I use autocommands to show the statusline. This lets me show different statuslines for different buffers and add an inactive statusline. Credit to elianiva for the concept.

vim.api.nvim_exec([[
  augroup Statusline
  au!
  au WinEnter,BufEnter * setlocal statusline=%!v:lua.Statusline.active()
  au WinLeave,BufLeave * setlocal statusline=%!v:lua.Statusline.inactive()
  au WinEnter,BufEnter,FileType NvimTree setlocal statusline=%!v:lua.Statusline.short()
  augroup END
]], false)

6. Bonus modules

Some extra modules that I don't use, but you may be interested in.

6.1. Git Info

Many people like to have git info in their statusline.
To use it, chuck this function into your file and add it to Statusline.active().

(requires gitsigns.nvim)

local vcs = function()
  local git_info = vim.b.gitsigns_status_dict
  if not git_info or git_info.head == "" then
    return ""
  end
  local added = git_info.added and ("%#GitSignsAdd#+" .. git_info.added .. " ") or ""
  local changed = git_info.changed and ("%#GitSignsChange#~" .. git_info.changed .. " ") or ""
  local removed = git_info.removed and ("%#GitSignsDelete#-" .. git_info.removed .. " ") or ""
  if git_info.added == 0 then
    added = ""
  end
  if git_info.changed == 0 then
    changed = ""
  end
  if git_info.removed == 0 then
    removed = ""
  end
  return table.concat {
     " ",
     added,
     changed,
     removed,
     " ",
     "%#GitSignsAdd# ",
     git_info.head,
     " %#Normal#",
  }
end