Toggle comments in Neovim, using built in commentstring filetype option; written in Lua. Without a doubt this plugin is not required and is a rip off of TPope's Commentary with less features! What makes this plugin stand out over the numerous other comment plugins written in Lua are:

• Comments each line, rather than adds block comments; making it easier to toggle code when debugging
• Uses the built in commentstring buffer option to define comment markers
• Where a marker doesn't have a space character as padding this is added, configurable (this can be disabled in the options, see below but is useful when working with numerous linters)
• Supports motions
• Dot . repeatable

When the plugin is called it works out the range to comment/uncomment; if all lines in the given range are commented then it uncomments, otherwise it comments the range. This is useful when commenting a block out for testing with a real like comment in it; as for the plugin a comment is a comment.

Either use the command CommentToggle, e.g.:

• CommentToggle comment/uncomment current line
• 67,69CommentToggle comment/uncomment a range
• '<,'>CommentToggle comment/uncomment a visual selection

Or use the default mappings:

• gcc comment/uncomment current line, this does not take a count, if you want a count use the gc{count}{motion}
• gc{motion} comment/uncomment selection defined by a motion (as lines are commented, any comment toggling actions will default to a linewise):
  • gcip comment/uncomment a paragraph
  • gc4w comment/uncomment current line
  • gc4j comment/uncomment 4 lines below the current line
  • dic delete comment block
  • gcic uncomment commented block

The comment plugin needs to be initialised using:

require('nvim_comment').setup()

However you can pass in some config options, the defaults are:

{
  -- Linters prefer comment and line to have a space in between markers
  marker_padding = true,
  -- should comment out empty or whitespace only lines
  comment_empty = true,
  -- trim empty comment whitespace
  comment_empty_trim_whitespace = true,
  -- Should key mappings be created
  create_mappings = true,
  -- Normal mode mapping left hand side
  line_mapping = "gcc",
  -- Visual/Operator mapping left hand side
  operator_mapping = "gc",
  -- text object mapping, comment chunk,,
  comment_chunk_text_object = "ic",
  -- Hook function to call before commenting takes place
  hook = nil
}

• Ignore Empty Lines

require('nvim_comment').setup({comment_empty = false})

• Don't trim trailing comment whitespace when commenting empty line

require('nvim_comment').setup({comment_empty_trim_whitespace = false})

The default for this is true, meaning that a commented empty line will not contain any whitespace. Most commentstring comment prefixes have some whitespace padding, disable this to keep that padding on empty lines.

• Disable mappings

require('nvim_comment').setup({create_mappings = false})

• Custom mappings

require('nvim_comment').setup({line_mapping = "<leader>cl", operator_mapping = "<leader>c", comment_chunk_text_object = "ic"})

• Disable marker padding

require('nvim_comment').setup({marker_padding = false})

• Hook function called before reading commentstring

You can run arbitrary function which will be called before plugin reads value of commentstring. This can be used to integrate with JoosepAlviste/nvim-ts-context-commentstring:

require('nvim_comment').setup({
  hook = function()
    if vim.api.nvim_buf_get_option(0, "filetype") == "vue" then
      require("ts_context_commentstring.internal").update_commentstring()
    end
  end
})

• Changing/Setting commentstring

If you want to override the comment markers or add a new filetype just set the commentstring options:

-- Assumes this is being run in the context of the filetype...
vim.api.nvim_buf_set_option(0, "commentstring", "# %s")

You can also use an autocommand to automatically load your commentstring for certain file types:

" when you enter a (new) buffer
augroup set-commentstring-ag
autocmd!
autocmd BufEnter *.cpp,*.h :lua vim.api.nvim_buf_set_option(0, "commentstring", "// %s")
" when you've changed the name of a file opened in a buffer, the file type may have changed
autocmd BufFilePost *.cpp,*.h :lua vim.api.nvim_buf_set_option(0, "commentstring", "// %s")
augroup END

Or add the comment string option in the relevant filetype file:

let commentstring="# %s"

vim.api.nvim_buf_set_option(0, "commentstring", "# %s")

Install just as you would a normal plugin, here are some options:

mkdir -p ~/.local/share/nvim/site/pack/plugins/start
cd ~/.local/share/nvim/site/pack/plugins/start
git clone https://github.com/terrortylor/nvim-comment

Using packer.nvim:

use "terrortylor/nvim-comment"
require('nvim_comment').setup()