my-nvim-setup/lua/plugins/configs/bufferline.lua

local present, bufferline = pcall(require, "bufferline")

if not present then
   return
end

require("base46").load_highlight "bufferline"

vim.cmd [[

 function! Toggle_theme(a,b,c,d)
   lua require('base46').toggle_theme()
 endfunction

 function! Quit_vim(a,b,c,d)
     qa
 endfunction
]]

local options = {
   options = {
      offsets = { { filetype = "NvimTree", text = "", padding = 1 } },
      buffer_close_icon = "",
      modified_icon = "",
      close_icon = "",
      show_close_icon = false,
      left_trunc_marker = " ",
      right_trunc_marker = " ",
      max_name_length = 20,
      max_prefix_length = 13,
      tab_size = 20,
      show_tab_indicators = true,
      enforce_regular_tabs = false,
      show_buffer_close_icons = true,
      separator_style = "thin",
      themable = true,

      -- top right buttons in bufferline
      custom_areas = {
         right = function()
            return {
               { text = "%@Toggle_theme@" .. vim.g.toggle_theme_icon .. "%X" },
               { text = "%@Quit_vim@ %X" },
            }
         end,
      },
   },
}

-- check for any override
options = require("core.utils").load_override(options, "akinsho/bufferline.nvim")

bufferline.setup(options)