starter/lua/plugins/visualize/fold.lua

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
return {
	"kevinhwang91/nvim-ufo",
	dependencies = "kevinhwang91/promise-async",
	event = "BufReadPre",
	config = function()
		local capabilities = vim.lsp.protocol.make_client_capabilities()
		capabilities.textDocument.foldingRange = {
			dynamicRegistration = false,
			lineFoldingOnly = true,
		}
		local language_servers = require("lspconfig").util.available_servers()
		for _, ls in ipairs(language_servers) do
			require("lspconfig")[ls].setup({
				capabilities = capabilities,
			})
		end
	end,
	opts = {
		fold_virt_text_handler = handler,
		provider_selector = function(bufnr, filetype, buftype)
			return { "treesitter", "indent" }
		end,
	},
}