Add better mock typedef for FiberNode

src/mocked-types/index.ts

@@ -1,5 +1,55 @@
-export interface FiberNode {
+import * as React from "react";
+
+export type FiberNode = FiberNodeForComponentClass | FiberNodeForFunctionComponent | FiberNodeForInstrinsicElement | FiberNodeForTextNode;
+
+export interface FiberNodeForFunctionComponent {
   child: FiberNode | null;
   sibling: FiberNode | null;
-  // Add type
+
+  elementType: React.FunctionComponent;
+  type: React.FunctionComponent;
+
+  stateNode: null;
 }
+
+export interface FiberNodeForComponentClass {
+  child: FiberNode | null;
+  sibling: FiberNode | null;
+
+  elementType: React.ComponentClass;
+  type: React.ComponentClass;
+
+  stateNode: React.Component;
+}
+
+export interface FiberNodeForInstrinsicElement {
+  child: FiberNode | null;
+  sibling: FiberNode | null;
+
+  elementType: keyof JSX.IntrinsicElements;
+  type: keyof JSX.IntrinsicElements;
+
+  stateNode: HTMLElement;
+}
+
+export interface FiberNodeForInstrinsicElement {
+  child: FiberNode | null;
+  sibling: FiberNode | null;
+
+  elementType: keyof JSX.IntrinsicElements;
+  type: keyof JSX.IntrinsicElements;
+
+  stateNode: HTMLElement;
+}
+
+export interface FiberNodeForTextNode {
+  child: null;
+  sibling: FiberNode | null;
+
+  elementType: null;
+  type: null;
+
+  stateNode: Text;
+}
+
+export type FiberNodeisHTMLLike  = FiberNodeForInstrinsicElement | FiberNodeForTextNode;