Merge pull request #33044 from eps1lon/react-dom/findDOMNode-optional

[react-dom] Allow maybe instance in findDOMNode

types/react-dom/index.d.ts

@@ -17,7 +17,7 @@ import {
     DOMAttributes, DOMElement, ReactNode, ReactPortal
 } from 'react';
 
-export function findDOMNode(instance: ReactInstance): Element | null | Text;
+export function findDOMNode(instance: ReactInstance | null | undefined): Element | null | Text;
 export function unmountComponentAtNode(container: Element): boolean;
 
 export function createPortal(children: ReactNode, container: Element, key?: null | string): ReactPortal;

types/react-dom/react-dom-tests.tsx

@@ -30,6 +30,8 @@ describe('ReactDOM', () => {
         const rootElement = document.createElement('div');
         ReactDOM.render(React.createElement('div'), rootElement);
         ReactDOM.findDOMNode(rootElement);
+        ReactDOM.findDOMNode(null);
+        ReactDOM.findDOMNode(undefined);
     });
 
     it('createPortal', () => {

types/react-dom/v15/index.d.ts

@@ -15,7 +15,7 @@ import {
     DOMAttributes, DOMElement
 } from 'react';
 
-export function findDOMNode<E extends Element>(instance: ReactInstance): E;
+export function findDOMNode<E extends Element>(instance: ReactInstance | null | undefined): E;
 export function findDOMNode(instance: ReactInstance): Element;
 
 export function render<P extends DOMAttributes<T>, T extends Element>(

types/react-dom/v15/react-dom-tests.ts

@@ -25,6 +25,8 @@ describe('ReactDOM', () => {
         const rootElement = document.createElement('div');
         ReactDOM.render(React.createElement('div'), rootElement);
         ReactDOM.findDOMNode(rootElement);
+        ReactDOM.findDOMNode(null);
+        ReactDOM.findDOMNode(undefined);
     });
 });