[internal] Refactor useForkRef TS types: tighten cleanupRef and simplify ref typing (#46967)

Co-authored-by: Zeeshan Tamboli <[email protected]>

Author: wo-o29

packages/mui-utils/src/useForkRef/useForkRef.ts

@@ -19,9 +19,9 @@ import * as React from 'react';
 export default function useForkRef<Instance>(
   ...refs: Array<React.Ref<Instance> | undefined>
 ): React.RefCallback<Instance> | null {
-  const cleanupRef = React.useRef<void | (() => void)>(undefined);
+  const cleanupRef = React.useRef<() => void>(undefined);
 
-  const refEffect = React.useCallback((instance: Instance | null) => {
+  const refEffect = React.useCallback((instance: Instance) => {
     const cleanups = refs.map((ref) => {
       if (ref == null) {
         return null;
@@ -37,9 +37,9 @@ export default function useForkRef<Instance>(
             };
       }
 
-      (ref as React.RefObject<Instance | null>).current = instance;
+      ref.current = instance;
       return () => {
-        (ref as React.RefObject<Instance | null>).current = null;
+        ref.current = null;
       };
     });
 
@@ -57,11 +57,11 @@ export default function useForkRef<Instance>(
     return (value) => {
       if (cleanupRef.current) {
         cleanupRef.current();
-        (cleanupRef as React.RefObject<void | (() => void)>).current = undefined;
+        cleanupRef.current = undefined;
       }
 
       if (value != null) {
-        (cleanupRef as React.RefObject<void | (() => void)>).current = refEffect(value);
+        cleanupRef.current = refEffect(value);
       }
     };
     // TODO: uncomment once we enable eslint-plugin-react-compiler // eslint-disable-next-line react-compiler/react-compiler -- intentionally ignoring that the dependency array must be an array literal