only add this._slotted if necessary

src/generators/dom/index.ts

@@ -181,7 +181,7 @@ export default function dom(
 			this._root = options._root || this;
 			this._yield = options._yield;
 			this._bind = options._bind;
-			this._slotted = options.slots || {};
+			${generator.slots.size && `this._slotted = options.slots || {};`}
 
 			${generator.stylesheet.hasStyles &&
 				options.css !== false &&

test/js/index.js

@@ -4,7 +4,7 @@ import * as path from "path";
 import { rollup } from "rollup";
 import { loadConfig, svelte } from "../helpers.js";
 
-describe.skip("js", () => {
+describe("js", () => {
 	fs.readdirSync("test/js/samples").forEach(dir => {
 		if (dir[0] === ".") return;