Made fragment/async/strict mode checks more strict

Author: bvaughn

packages/react-is/src/ReactIs.js

@@ -45,7 +45,9 @@ export function typeOf(object: any) {
     case REACT_ASYNC_MODE_TYPE:
     case REACT_FRAGMENT_TYPE:
     case REACT_STRICT_MODE_TYPE:
-      return maybeType;
+      if (getTypeOf(object) === REACT_ELEMENT_TYPE) {
+        return maybeType;
+      }
   }
 
   maybeType = getTypeTypeOf(object);
@@ -72,7 +74,10 @@ export const Portal = REACT_PORTAL_TYPE;
 export const StrictMode = REACT_STRICT_MODE_TYPE;
 
 export function isAsyncMode(object: any) {
-  return getType(object) === REACT_ASYNC_MODE_TYPE;
+  return (
+    getType(object) === REACT_ASYNC_MODE_TYPE &&
+    getTypeOf(object) === REACT_ELEMENT_TYPE
+  );
 }
 export function isContextConsumer(object: any) {
   return getTypeTypeOf(object) === REACT_CONTEXT_TYPE;
@@ -84,11 +89,17 @@ export function isElement(object: any) {
   return getTypeOf(object) === REACT_ELEMENT_TYPE;
 }
 export function isFragment(object: any) {
-  return getType(object) === REACT_FRAGMENT_TYPE;
+  return (
+    getType(object) === REACT_FRAGMENT_TYPE &&
+    getTypeOf(object) === REACT_ELEMENT_TYPE
+  );
 }
 export function isPortal(object: any) {
   return getTypeOf(object) === REACT_PORTAL_TYPE;
 }
 export function isStrictMode(object: any) {
-  return getType(object) === REACT_STRICT_MODE_TYPE;
+  return (
+    getType(object) === REACT_STRICT_MODE_TYPE &&
+    getTypeOf(object) === REACT_ELEMENT_TYPE
+  );
 }

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

@@ -26,6 +26,7 @@ describe('ReactIs', () => {
       ReactIs.AsyncMode,
     );
     expect(ReactIs.isAsyncMode(<React.unstable_AsyncMode />)).toBe(true);
+    expect(ReactIs.isAsyncMode({type: ReactIs.AsyncMode})).toBe(false);
     expect(ReactIs.isAsyncMode(<React.StrictMode />)).toBe(false);
     expect(ReactIs.isAsyncMode(<div />)).toBe(false);
   });
@@ -65,6 +66,7 @@ describe('ReactIs', () => {
   it('should identify fragments', () => {
     expect(ReactIs.typeOf(<React.Fragment />)).toBe(ReactIs.Fragment);
     expect(ReactIs.isFragment(<React.Fragment />)).toBe(true);
+    expect(ReactIs.isFragment({type: ReactIs.Fragment})).toBe(false);
     expect(ReactIs.isFragment('React.Fragment')).toBe(false);
     expect(ReactIs.isFragment(<div />)).toBe(false);
     expect(ReactIs.isFragment([])).toBe(false);
@@ -81,6 +83,7 @@ describe('ReactIs', () => {
   it('should identify strict mode', () => {
     expect(ReactIs.typeOf(<React.StrictMode />)).toBe(ReactIs.StrictMode);
     expect(ReactIs.isStrictMode(<React.StrictMode />)).toBe(true);
+    expect(ReactIs.isStrictMode({type: ReactIs.StrictMode})).toBe(false);
     expect(ReactIs.isStrictMode(<React.unstable_AsyncMode />)).toBe(false);
     expect(ReactIs.isStrictMode(<div />)).toBe(false);
   });