Add utils - Methods to check if a node corresponds to functional or class components

src/utils.ts

@@ -1,4 +1,5 @@
-import { FiberNode, FiberNodeisHTMLLike } from './mocked-types';
+import * as React from 'react';
+import { FiberNode, FiberNodeisHTMLLike, FiberNodeForFunctionComponent, FiberNodeForComponentClass } from './mocked-types';
 
 function isNodeHtmlLike(node: FiberNode): node is FiberNodeisHTMLLike {
     return (typeof node.type === "string") || node.type === null;
@@ -8,4 +9,12 @@ function isNodeNotHtmlLike(node: FiberNode): node is Exclude<FiberNode, FiberNod
     return !isNodeHtmlLike(node);
 }
 
-export { isNodeHtmlLike, isNodeNotHtmlLike };
+function isNodeFunctionComponent(node: FiberNode): node is FiberNodeForFunctionComponent {
+    return isNodeNotHtmlLike(node) && node.stateNode === null;
+}
+
+function isNodeComponentClass(node: FiberNode): node is FiberNodeForComponentClass {
+    return isNodeNotHtmlLike(node) && (node.stateNode instanceof React.Component);
+}
+
+export { isNodeHtmlLike, isNodeNotHtmlLike, isNodeFunctionComponent, isNodeComponentClass };