nvim-ufo

The goal of nvim-ufo is to make Neovim's fold look modern and keep high performance.

https://user-images.githubusercontent.com/17562139/173796287-9842fb3a-37c2-47fb-8968-6e7600c0fcef.mp4

setup foldcolumn like demo

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Table of contents

• Table of contents
• Features
• Quickstart
  • Requirements
  • Installation
  • Minimal configuration
  • Usage
• Documentation
  • How does nvim-ufo get the folds?
  • Setup and description
  • Preview function table
  • Commands
  • API
  • Highlight groups
• Advanced configuration
  • Customize configuration
  • Customize fold text
• Feedback
• License

Features

• Penetrate color for folded lines like other modern editors/IDEs
• Never block Neovim
• Adding folds high accuracy with Folding Range in LSP
• Support fallback and customize strategy for fold provider
• Peek folded line and jump the desired location with less redraw

Quickstart

Requirements

• Neovim 0.7.2 or later
• coc.nvim (optional)

Installation

Install with Packer.nvim:

use {'kevinhwang91/nvim-ufo', requires = 'kevinhwang91/promise-async'}

Minimal configuration

use {'kevinhwang91/nvim-ufo', requires = 'kevinhwang91/promise-async'}

vim.o.foldcolumn = '1' -- '0' is not bad
vim.o.foldlevel = 99 -- Using ufo provider need a large value, feel free to decrease the value
vim.o.foldlevelstart = 99
vim.o.foldenable = true

-- Using ufo provider need remap `zR` and `zM`. If Neovim is 0.6.1, remap yourself
vim.keymap.set('n', 'zR', require('ufo').openAllFolds)
vim.keymap.set('n', 'zM', require('ufo').closeAllFolds)

-- Option 1: coc.nvim as LSP client
use {'neoclide/coc.nvim', branch = 'master', run = 'yarn install --frozen-lockfile'}
require('ufo').setup()
--

-- Option 2: nvim lsp as LSP client
-- Tell the server the capability of foldingRange,
-- Neovim hasn't added foldingRange to default capabilities, users must add it manually
local capabilities = vim.lsp.protocol.make_client_capabilities()
capabilities.textDocument.foldingRange = {
    dynamicRegistration = false,
    lineFoldingOnly = true
}
local language_servers = require("lspconfig").util.available_servers() -- or list servers manually like {'gopls', 'clangd'}
for _, ls in ipairs(language_servers) do
    require('lspconfig')[ls].setup({
        capabilities = capabilities
        -- you can add other fields for setting up lsp server in this table
    })
end
require('ufo').setup()
--

-- Option 3: treesitter as a main provider instead
-- (Note: the `nvim-treesitter` plugin is *not* needed.)
-- ufo uses the same query files for folding (queries/<lang>/folds.scm)
-- performance and stability are better than `foldmethod=nvim_treesitter#foldexpr()`
require('ufo').setup({
    provider_selector = function(bufnr, filetype, buftype)
        return {'treesitter', 'indent'}
    end
})
--

-- Option 4: disable all providers for all buffers
-- Not recommend, AFAIK, the ufo's providers are the best performance in Neovim
require('ufo').setup({
    provider_selector = function(bufnr, filetype, buftype)
        return ''
    end
})

Usage

Use fold as usual.

Using a provider of ufo, must set a large value for foldlevel, this is the limitation of foldmethod=manual. A small value may close fold automatically if the fold ranges updated.

After running zR and zM normal commands will change the foldlevel, ufo provide the APIs openAllFolds/closeAllFolds to open/close all folds but keep foldlevel value, need to remap them.

Like zR and zM, if you used zr and zm before, please use closeFoldsWith API to close folds like set foldlevel=n but keep foldlevel value.

Documentation

How does nvim-ufo get the folds?

If ufo detect foldmethod option is not diff or marker, it will request the providers to get the folds, the request strategy is formed by the main and the fallback. The default value of main is lsp and the default value of fallback is indent which implemented by ufo.

For example, Changing the text in a buffer will request the providers for folds.

foldmethod option will finally become manual if ufo is working.

Setup and description

{
    open_fold_hl_timeout = {
        description = [[Time in millisecond between the range to be highlgihted and to be cleared
                    while opening the folded line, `0` value will disable the highlight]],
        default = 400
    },
    provider_selector = {
        description = [[A function as a selector for fold providers. For now, there are
                    'lsp' and 'treesitter' as main provider, 'indent' as fallback provider]],
        default = nil
    },
    close_fold_kinds_for_ft = {
        description = [[After the buffer is displayed (opened for the first time), close the
                    folds whose range with `kind` field is included in this option. For now,
                    'lsp' provider's standardized kinds are 'comment', 'imports' and 'region'.
                    This option is a table with filetype as key and fold kinds as value. Use a
                    default value if value of filetype is absent.
                    Run `UfoInspect` for details if your provider has extended the kinds.]],
        default = {default = {}}
    },
    fold_virt_text_handler = {
        description = [[A function customize fold virt text, see ### Customize fold text]],
        default = nil
    },
    enable_get_fold_virt_text = {
        description = [[Enable a function with `lnum` as a parameter to capture the virtual text
                    for the folded lines and export the function to `get_fold_virt_text` field of
                    ctx table as 6th parameter in `fold_virt_text_handler`]],
        default = false
    },
    preview = {
        description = [[Configure the options for preview window and remap the keys for current
                    buffer and preview buffer if the preview window is displayed.
                    Never worry about the users's keymaps are overridden by ufo, ufo will save
                    them and restore them if preview window is closed.]],
        win_config = {
            border = {
                description = [[The border for preview window,
                    `:h nvim_open_win() | call search('border:')`]],
                default = 'rounded',
            },
            winblend = {
                description = [[The winblend for preview window, `:h winblend`]],
                default = 12,
            },
            winhighlight = {
                description = [[The winhighlight for preview window, `:h winhighlight`]],
                default = 'Normal:Normal',
            },
            maxheight = {
                description = [[The max height of preview window]],
                default = 20,
            }
        },
        mappings = {
            description = [[The table for {function = key}]],
            default = [[see ###Preview function table for detail]],
        }
    }
}

:h ufo may help you to get the all default configuration.

Preview function table

Function	Action	Def Key
scrollB	Type CTRL-B in preview window
scrollF	Type CTRL-F in preview window
scrollU	Type CTRL-U in preview window
scrollD	Type CTRL-D in preview window
scrollE	Type CTRL-E in preview window	<C-E>
scrollY	Type CTRL-Y in preview window	<C-Y>
jumpTop	Jump to top region in preview window
jumpBot	Jump to bottom region in preview window
close	In normal window: Close preview windowIn preview window: Close preview window	q
switch	In normal window: Go to preview windowIn preview window: Go to normal window	<Tab>
trace	In normal window: Trace code based on toplineIn preview window: Trace code based on cursor	<CR>

Additional mouse supported:

1. <ScrollWheelUp> and <ScrollWheelDown>: Scroll preview window.
2. <2-LeftMouse>: Same as trace action in preview window.

trace action will open all fold for the folded lines

Commands

Command	Description
UfoEnable	Enable ufo
UfoDisable	Disable ufo
UfoInspect	Inspect current buffer information
UfoAttach	Attach current buffer to enable all features
UfoDetach	Detach current buffer to disable all features
UfoEnableFold	Enable to get folds and update them at once for current buffer
UfoDisableFold	Disable to get folds for current buffer

API

ufo.lua

Highlight groups

" hi default UfoFoldedFg guifg=Normal.foreground
" hi default UfoFoldedBg guibg=Folded.background
hi default link UfoPreviewSbar PmenuSbar
hi default link UfoPreviewThumb PmenuThumb
hi default link UfoPreviewWinBar UfoFoldedBg
hi default link UfoPreviewCursorLine Visual
hi default link UfoFoldedEllipsis Comment
hi default link UfoCursorFoldedLine CursorLine

• UfoFoldedFg: Foreground for raw text of folded line.
• UfoFoldedBg: Background of folded line.
• UfoPreviewSbar: Scroll bar of preview window, only take effect if the border is missing right horizontal line, like border = 'none'.
• UfoPreviewCursorLine: Highlight current line in preview window if it isn't the start of folded lines.
• UfoPreviewWinBar: Virtual winBar of preview window.
• UfoPreviewThumb: Thumb of preview window.
• UfoFoldedEllipsis: Ellipsis at the end of folded line, invalid if fold_virt_text_handler is set.
• UfoCursorFoldedLine: Highlight the folded line under the cursor

Advanced configuration

Configuration can be found at example.lua

Customize configuration

local ftMap = {
    vim = 'indent',
    python = {'indent'},
    git = ''
}
require('ufo').setup({
    open_fold_hl_timeout = 150,
    close_fold_kinds_for_ft = {
        default = {'imports', 'comment'},
        json = {'array'},
        c = {'comment', 'region'}
    },
    preview = {
        win_config = {
            border = {'', '─', '', '', '', '─', '', ''},
            winhighlight = 'Normal:Folded',
            winblend = 0
        },
        mappings = {
            scrollU = '<C-u>',
            scrollD = '<C-d>',
            jumpTop = '[',
            jumpBot = ']'
        }
    },
    provider_selector = function(bufnr, filetype, buftype)
        -- if you prefer treesitter provider rather than lsp,
        -- return ftMap[filetype] or {'treesitter', 'indent'}
        return ftMap[filetype]

        -- refer to ./doc/example.lua for detail
    end
})
vim.keymap.set('n', 'zR', require('ufo').openAllFolds)
vim.keymap.set('n', 'zM', require('ufo').closeAllFolds)
vim.keymap.set('n', 'zr', require('ufo').openFoldsExceptKinds)
vim.keymap.set('n', 'zm', require('ufo').closeFoldsWith) -- closeAllFolds == closeFoldsWith(0)
vim.keymap.set('n', 'K', function()
    local winid = require('ufo').peekFoldedLinesUnderCursor()
    if not winid then
        -- choose one of coc.nvim and nvim lsp
        vim.fn.CocActionAsync('definitionHover') -- coc.nvim
        vim.lsp.buf.hover()
    end
end)

Customize fold text

Adding number suffix of folded lines instead of the default ellipsis, here is the example:

local handler = function(virtText, lnum, endLnum, width, truncate)
    local newVirtText = {}
    local suffix = (' 󰁂 %d '):format(endLnum - lnum)
    local sufWidth = vim.fn.strdisplaywidth(suffix)
    local targetWidth = width - sufWidth
    local curWidth = 0
    for _, chunk in ipairs(virtText) do
        local chunkText = chunk[1]
        local chunkWidth = vim.fn.strdisplaywidth(chunkText)
        if targetWidth > curWidth + chunkWidth then
            table.insert(newVirtText, chunk)
        else
            chunkText = truncate(chunkText, targetWidth - curWidth)
            local hlGroup = chunk[2]
            table.insert(newVirtText, {chunkText, hlGroup})
            chunkWidth = vim.fn.strdisplaywidth(chunkText)
            -- str width returned from truncate() may less than 2nd argument, need padding
            if curWidth + chunkWidth < targetWidth then
                suffix = suffix .. (' '):rep(targetWidth - curWidth - chunkWidth)
            end
            break
        end
        curWidth = curWidth + chunkWidth
    end
    table.insert(newVirtText, {suffix, 'MoreMsg'})
    return newVirtText
end

-- global handler
-- `handler` is the 2nd parameter of `setFoldVirtTextHandler`,
-- check out `./lua/ufo.lua` and search `setFoldVirtTextHandler` for detail.
require('ufo').setup({
    fold_virt_text_handler = handler
})

-- buffer scope handler
-- will override global handler if it is existed
-- local bufnr = vim.api.nvim_get_current_buf()
-- require('ufo').setFoldVirtTextHandler(bufnr, handler)

Feedback

• If you get an issue or come up with an awesome idea, don't hesitate to open an issue in github.
• If you think this plugin is useful or cool, consider rewarding it a star.

License

The project is licensed under a BSD-3-clause license. See LICENSE file for details.