config.nvim/lua/plugins/cmp.lua

require("luasnip.loaders.from_vscode").lazy_load()

local has_words_before = function()
	unpack = unpack or table.unpack
	local line, col = unpack(vim.api.nvim_win_get_cursor(0))
	return col ~= 0 and vim.api.nvim_buf_get_lines(0, line - 1, line, true)[1]:sub(col, col):match("%s") == nil
end

local luasnip = require("luasnip")
local cmp = require("cmp")


cmp.setup({
	-- ... Your other configuration ...
	snippet = {
		-- REQUIRED - you must specify a snippet engine
		expand = function(args)
			-- vim.fn["vsnip#anonymous"](args.body) -- For `vsnip` users.
			require('luasnip').lsp_expand(args.body) -- For `luasnip` users.
			-- require('snippy').expand_snippet(args.body) -- For `snippy` users.
			-- vim.fn["UltiSnips#Anon"](args.body) -- For `ultisnips` users.
		end,
	},
	mapping = {
		["<Tab>"] = cmp.mapping(function(fallback)
			if cmp.visible() then
				cmp.confirm({ select = true })
			elseif luasnip.expand_or_jumpable() then
				luasnip.expand_or_jump()
			elseif has_words_before() then
				cmp.complete()
			else
				fallback()
			end
		end, { "i", "s" }),
		["<S-Tab>"] = cmp.mapping(function(fallback)
			if cmp.visible() then
				cmp.select_prev_item()
			elseif luasnip.jumpable(-1) then
				luasnip.jump(-1)
			else
				fallback()
			end
		end, { "i", "s" }),
		['<C-b>'] = cmp.mapping.scroll_docs(-4),
		['<C-f>'] = cmp.mapping.scroll_docs(4),
		['<C-n>'] = cmp.mapping.select_next_item(),
		['<C-p>'] = cmp.mapping.select_prev_item(),
		['<C-Space>'] = cmp.mapping.complete(),
		['<C-e>'] = cmp.mapping.abort(),
		['<CR>'] = cmp.mapping.confirm({ select = true }), -- Accept currently selected item. Set `select` to `false` to only confirm explicitly selected items
		-- ... Your other mappings ...
	},
	sources = cmp.config.sources({
		{ name = "luasnip" }, -- For luasnip users.
		{ name = "nvim_lsp" },
		{ name = 'nvim_lua' },
		{ name = "treesitter" },
		{ name = "async_path" },
		{ name = "gitmoji" },
		{ name = "buffer" },
	}),
	completion = {
		completeopt = 'menu,menuone,noinsert'
	}
})

cmp.setup.cmdline({ '/', '?' }, {
	mapping = cmp.mapping.preset.cmdline(),
	completion = {
		completeopt = 'menu,menuone,noselect'
	},
	sources = {
		{ name = 'buffer' }
	},
})

-- `:` cmdline setup.
cmp.setup.cmdline(':', {
	mapping = cmp.mapping.preset.cmdline(),
	completion = {
		completeopt = 'menu,menuone,noselect'
	},
	sources = cmp.config.sources({
		{ name = 'path' }
	}, {
		{
			name = 'cmdline',
			option = {
				ignore_cmds = {}
			}
		}
	})
})

-- nvim-cmp
-- If you want insert `(` after select function or method item
local cmp_autopairs = require('nvim-autopairs.completion.cmp')
local cmp = require('cmp')
cmp.event:on(
	'confirm_done',
	cmp_autopairs.on_confirm_done()
)