improve nvim-cmp

lua/custom/nvim-cmp.lua

@@ -19,6 +19,11 @@ end
 -- load vs-code like snippets from plugins (e.g. friendly-snippets)
 require("luasnip/loaders/from_vscode").lazy_load()
 
+local function has_words_before()
+	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
+
 vim.opt.completeopt = "menu,menuone,noselect"
 
 cmp.setup({
@@ -34,20 +39,40 @@ cmp.setup({
 	},
 
 	mapping = cmp.mapping.preset.insert({
-		["<C-k>"] = cmp.mapping.select_prev_item(), -- previous suggestion
-		["<C-j>"] = cmp.mapping.select_next_item(), -- next suggestion
+		["<C-k>"] = 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-j>"] = cmp.mapping(function(fallback)
+			if cmp.visible() then
+				cmp.select_next_item()
+			elseif luasnip.expand_or_jumpable() then
+				luasnip.expand_or_jump()
+			elseif has_words_before() then
+				cmp.complete()
+			else
+				fallback()
+			end
+		end, { "i", "s" }),
+
 		["<C-b>"] = cmp.mapping.scroll_docs(-4),
 		["<C-f>"] = cmp.mapping.scroll_docs(4),
-		["<C-Space>"] = cmp.mapping.complete(), -- show completion suggestions
-		["<C-e>"] = cmp.mapping.abort(), -- close completion window
+		["<C-Space>"] = cmp.mapping.complete(),
+		["<C-e>"] = cmp.mapping.abort(),
 		["<CR>"] = cmp.mapping.confirm({ select = true }),
 	}),
 	-- sources for autocompletion
 	sources = cmp.config.sources({
-		{ name = "nvim_lsp" },      -- lsp
-		{ name = "luasnip" },       -- snippets
+		{ name = "nvim_lsp" },              -- lsp
+		{ name = "luasnip" },               -- snippets
 		{ name = "buffer",  keyword_length = 5 }, -- text within current buffer
-		{ name = "path" },          -- file system paths
+		{ name = "path" },                  -- file system paths
 	}),
 	-- configure lspkind for vs-code like icons
 	formatting = {