test: add test case

Author: zombieJ

src/SingleObserver/index.tsx

@@ -38,7 +38,10 @@ function SingleObserver(props: SingleObserverProps, ref: React.Ref<HTMLElement>)
 
   const getDom = () =>
     findDOMNode<HTMLElement>(elementRef.current) ||
-    findDOMNode<HTMLElement>((elementRef.current as any)?.nativeElement) ||
+    // Support `nativeElement` format
+    (elementRef.current && typeof elementRef.current === 'object'
+      ? findDOMNode<HTMLElement>((elementRef.current as any)?.nativeElement)
+      : null) ||
     findDOMNode<HTMLElement>(wrapperRef.current);
 
   React.useImperativeHandle(ref, () => getDom());

tests/ref.spec.tsx

@@ -24,4 +24,22 @@ describe('ResizeObserver.ref', () => {
 
     expect(resizeRef.current).toEqual(container.querySelector('.little'));
   });
+
+  it('ignore invalidate forward', () => {
+    const My = React.forwardRef((_, ref) => {
+      React.useImperativeHandle(ref, () => 233);
+
+      return <div className="little" />;
+    });
+
+    const resizeRef = React.createRef<HTMLDivElement>();
+
+    const { container } = render(
+      <ResizeObserver ref={resizeRef}>
+        <My />
+      </ResizeObserver>,
+    );
+
+    expect(resizeRef.current).toEqual(container.querySelector('.little'));
+  });
 });