add isNode to react-is

packages/react-is/src/ReactIs.js

@@ -90,6 +90,23 @@ export function isForwardRef(object: any) {
 export function isFragment(object: any) {
   return typeOf(object) === REACT_FRAGMENT_TYPE;
 }
+export function isNode(object: any) {
+  switch (typeof object) {
+    case 'number':
+    case 'string':
+    case 'undefined':
+      return true;
+    case 'boolean':
+      return !object;
+    case 'object':
+      if (Array.isArray(object)) {
+        return object.every(isNode);
+      }
+      return object === null || isElement(object);
+    default:
+      return false;
+  }
+}
 export function isProfiler(object: any) {
   return typeOf(object) === REACT_PROFILER_TYPE;
 }

packages/react-is/src/__tests__/ReactIs-test.js

@@ -85,6 +85,26 @@ describe('ReactIs', () => {
     expect(ReactIs.isContextConsumer(<div />)).toBe(false);
   });
 
+  it('should identify nodes', () => {
+    expect(ReactIs.isNode(<div />)).toBe(true);
+    expect(ReactIs.isNode('div')).toBe(true);
+    expect(ReactIs.isNode(false)).toBe(true);
+    expect(ReactIs.isNode(true)).toBe(false);
+    expect(ReactIs.isNode(123)).toBe(true);
+    expect(ReactIs.isNode(null)).toBe(true);
+    expect(ReactIs.isNode(undefined)).toBe(true);
+    expect(ReactIs.isNode([1, 'string', <div />])).toBe(true);
+    expect(ReactIs.isNode({})).toBe(false);
+
+    // It should also identify more specific types as nodes
+    const Context = React.createContext(false);
+    expect(ReactIs.isNode(<Context.Provider />)).toBe(true);
+    expect(ReactIs.isNode(<Context.Consumer />)).toBe(true);
+    expect(ReactIs.isNode(<React.Fragment />)).toBe(true);
+    expect(ReactIs.isNode(<React.unstable_AsyncMode />)).toBe(true);
+    expect(ReactIs.isNode(<React.StrictMode />)).toBe(true);
+  });
+
   it('should identify context providers', () => {
     const Context = React.createContext(false);
     expect(ReactIs.typeOf(<Context.Provider />)).toBe(ReactIs.ContextProvider);