nvim/after/plugin/barbar.lua

local enable = false
if (enable) then

    local map = vim.api.nvim_set_keymap
    local opts = { noremap = true, silent = true }

    -- Move to previous/next
    map('n', '<A-,>', '<Cmd>BufferPrevious<CR>', opts)
    map('n', '<A-.>', '<Cmd>BufferNext<CR>', opts)
    -- Re-order to previous/next
    map('n', '<A-<>', '<Cmd>BufferMovePrevious<CR>', opts)
    map('n', '<A->>', '<Cmd>BufferMoveNext<CR>', opts)
    -- Goto buffer in position...
    map('n', '<A-1>', '<Cmd>BufferGoto 1<CR>', opts)
    map('n', '<A-2>', '<Cmd>BufferGoto 2<CR>', opts)
    map('n', '<A-3>', '<Cmd>BufferGoto 3<CR>', opts)
    map('n', '<A-4>', '<Cmd>BufferGoto 4<CR>', opts)
    map('n', '<A-5>', '<Cmd>BufferGoto 5<CR>', opts)
    map('n', '<A-6>', '<Cmd>BufferGoto 6<CR>', opts)
    map('n', '<A-7>', '<Cmd>BufferGoto 7<CR>', opts)
    map('n', '<A-8>', '<Cmd>BufferGoto 8<CR>', opts)
    map('n', '<A-9>', '<Cmd>BufferGoto 9<CR>', opts)
    map('n', '<A-0>', '<Cmd>BufferLast<CR>', opts)
    -- Pin/unpin buffer
    map('n', '<A-p>', '<Cmd>BufferPin<CR>', opts)
    -- Close buffer
    map('n', '<A-c>', '<Cmd>BufferClose<CR>', opts)
    -- Wipeout buffer
    --                 :BufferWipeout
    -- Close commands
    --                 :BufferCloseAllButCurrent
    --                 :BufferCloseAllButPinned
    --                 :BufferCloseAllButCurrentOrPinned
    --                 :BufferCloseBuffersLeft
    --                 :BufferCloseBuffersRight
    -- Magic buffer-picking mode
    map('n', '<C-p>', '<Cmd>BufferPick<CR>', opts)
    -- Sort automatically by...
    map('n', '<Space>bb', '<Cmd>BufferOrderByBufferNumber<CR>', opts)
    map('n', '<Space>bn', '<Cmd>BufferOrderByName<CR>', opts)
    map('n', '<Space>bd', '<Cmd>BufferOrderByDirectory<CR>', opts)
    map('n', '<Space>bl', '<Cmd>BufferOrderByLanguage<CR>', opts)
    map('n', '<Space>bw', '<Cmd>BufferOrderByWindowNumber<CR>', opts)

    -- Other:
    -- :BarbarEnable - enables barbar (enabled by default)
    -- :BarbarDisable - very bad command, should never be used

    require'barbar'.setup {
        -- WARN: do not copy everything below into your config!
        --       It is just an example of what configuration options there are.
        --       The defaults are suitable for most people.

        -- Enable/disable animations
        animation = true,

        -- Automatically hide the tabline when there are this many buffers left.
        -- Set to any value >=0 to enable.
        auto_hide = false,

        -- Enable/disable current/total tabpages indicator (top right corner)
        tabpages = true,

        -- Enables/disable clickable tabs
        --  - left-click: go to buffer
        --  - middle-click: delete buffer
        clickable = true,

        -- Excludes buffers from the tabline
        exclude_ft = {'javascript'},
        exclude_name = {'package.json'},

        -- A buffer to this direction will be focused (if it exists) when closing the current buffer.
        -- Valid options are 'left' (the default), 'previous', and 'right'
        focus_on_close = 'left',

        -- Hide inactive buffers and file extensions. Other options are `alternate`, `current`, and `visible`.
        --hide = {extensions = true, inactive = true},

        -- Disable highlighting alternate buffers
        highlight_alternate = false,

        -- Disable highlighting file icons in inactive buffers
        highlight_inactive_file_icons = false,

        -- Enable highlighting visible buffers
        highlight_visible = true,

        icons = {
            -- Configure the base icons on the bufferline.
            -- Valid options to display the buffer index and -number are `true`, 'superscript' and 'subscript'
            buffer_index = true,
            buffer_number = false,
            button = '',
            -- Enables / disables diagnostic symbols
            diagnostics = {
                [vim.diagnostic.severity.ERROR] = {enabled = true, icon = 'ff'},
                [vim.diagnostic.severity.WARN] = {enabled = false},
                [vim.diagnostic.severity.INFO] = {enabled = false},
                [vim.diagnostic.severity.HINT] = {enabled = true},
            },
            gitsigns = {
                added = {enabled = true, icon = '+'},
                changed = {enabled = true, icon = '~'},
                deleted = {enabled = true, icon = '-'},
            },
            filetype = {
                -- Sets the icon's highlight group.
                -- If false, will use nvim-web-devicons colors
                custom_colors = false,

                -- Requires `nvim-web-devicons` if `true`
                enabled = true,
            },
            separator = {left = '▎', right = ''},

            -- If true, add an additional separator at the end of the buffer list
            separator_at_end = true,

            -- Configure the icons on the bufferline when modified or pinned.
            -- Supports all the base icon options.
            modified = {button = '●'},
            pinned = {button = '', filename = true},

            -- Use a preconfigured buffer appearance— can be 'default', 'powerline', or 'slanted'
            preset = 'default',

            -- Configure the icons on the bufferline based on the visibility of a buffer.
            -- Supports all the base icon options, plus `modified` and `pinned`.
            alternate = {filetype = {enabled = false}},
            current = {buffer_index = true},
            inactive = {button = '×'},
            visible = {modified = {buffer_number = false}},
        },

        -- If true, new buffers will be inserted at the start/end of the list.
        -- Default is to insert after current buffer.
        insert_at_end = false,
        insert_at_start = false,

        -- Sets the maximum padding width with which to surround each tab
        maximum_padding = 1,

        -- Sets the minimum padding width with which to surround each tab
        minimum_padding = 1,

        -- Sets the maximum buffer name length.
        maximum_length = 30,

        -- Sets the minimum buffer name length.
        minimum_length = 0,

        -- If set, the letters for each buffer in buffer-pick mode will be
        -- assigned based on their name. Otherwise or in case all letters are
        -- already assigned, the behavior is to assign letters in order of
        -- usability (see order below)
        semantic_letters = true,

        -- Set the filetypes which barbar will offset itself for
        sidebar_filetypes = {
            -- Use the default values: {event = 'BufWinLeave', text = '', align = 'left'}
            NvimTree = true,
            -- Or, specify the text used for the offset:
            undotree = {
                text = 'undotree',
                align = 'center', -- *optionally* specify an alignment (either 'left', 'center', or 'right')
            },
            -- Or, specify the event which the sidebar executes when leaving:
            ['neo-tree'] = {event = 'BufWipeout'},
            -- Or, specify all three
            Outline = {event = 'BufWinLeave', text = 'symbols-outline', align = 'right'},
        },

        -- New buffer letters are assigned in this order. This order is
        -- optimal for the qwerty keyboard layout but might need adjustment
        -- for other layouts.
        letters = 'asdfjkl;ghnmxcvbziowerutyqpASDFJKLGHNMXCVBZIOWERUTYQP',

        -- Sets the name of unnamed buffers. By default format is "[Buffer X]"
        -- where X is the buffer number. But only a static string is accepted here.
        no_name_title = nil,
    }
end