nvim config stolen from @Lukacms

nvim/lua/lsp/null-ls.lua

@@ -0,0 +1,37 @@
+local null_ls = require("null-ls")
+local b = null_ls.builtins
+
+-- https://github.com/jose-elias-alvarez/null-ls.nvim/pull/804
+local buf_path_in_workflow_folder = function()
+	local api = vim.api
+	local path = api.nvim_buf_get_name(api.nvim_get_current_buf())
+	return path:match("github/workflows/") ~= nil
+end
+
+local sources = {
+	b.diagnostics.actionlint.with({
+		runtime_condition = buf_path_in_workflow_folder,
+	}),
+
+	function()
+		local nl_utils = require("null-ls.utils").make_conditional_utils()
+		return nl_utils.root_has_file({ ".prettierrc.json", ".prettierrc" })
+				and b.formatting.prettierd.with({ filetypes = { "html", "javascript", "typescript", "svelte" } })
+			or b.formatting.eslint_d
+	end,
+
+	b.formatting.black,
+	b.formatting.stylua,
+}
+
+local M = {}
+
+M.setup = function(on_attach)
+	null_ls.setup({
+		debug = false,
+		sources = sources,
+		on_attach = on_attach,
+	})
+end
+
+return M