Add better type check utils for HTMLLike

src/utils.ts

@@ -1,5 +1,11 @@
-function isNodeSimple(node) {
+import { FiberNode, FiberNodeisHTMLLike } from './mocked-types';
+
+function isHtmlLike(node: FiberNode): node is FiberNodeisHTMLLike {
     return (typeof node.type === "string") || node.type === null;
 }
 
-export { isNodeSimple };
+function isNotHtmlLike(node: FiberNode): node is Exclude<FiberNode, FiberNodeisHTMLLike> {
+    return (typeof node.type === "string") || node.type === null;
+}
+
+export { isHtmlLike, isNotHtmlLike };