fix(react-native): bring back check for window.addEventListener (#3345)

because it does not exist in RN, but window is defined

Author: TkDodo

src/core/focusManager.ts

@@ -14,7 +14,9 @@ export class FocusManager extends Subscribable {
   constructor() {
     super()
     this.setup = onFocus => {
-      if (!isServer) {
+      // addEventListener does not exist in React Native, but window does
+      // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
+      if (!isServer && window.addEventListener) {
         const listener = () => onFocus()
         // Listen to visibillitychange and focus
         window.addEventListener('visibilitychange', listener, false)

src/core/onlineManager.ts

@@ -14,7 +14,9 @@ export class OnlineManager extends Subscribable {
   constructor() {
     super()
     this.setup = onOnline => {
-      if (!isServer) {
+      // addEventListener does not exist in React Native, but window does
+      // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
+      if (!isServer && window.addEventListener) {
         const listener = () => onOnline()
         // Listen to online
         window.addEventListener('online', listener, false)

src/core/tests/focusManager.test.tsx

@@ -73,6 +73,19 @@ describe('focusManager', () => {
     restoreIsServer()
   })
 
+  test('cleanup should still be undefined if window.addEventListener is not defined', async () => {
+    const { addEventListener } = globalThis.window
+
+    // @ts-expect-error
+    globalThis.window.addEventListener = undefined
+
+    const unsubscribe = focusManager.subscribe(() => undefined)
+    expect(focusManager['cleanup']).toBeUndefined()
+
+    unsubscribe()
+    globalThis.window.addEventListener = addEventListener
+  })
+
   it('should replace default window listener when a new event listener is set', async () => {
     const addEventListenerSpy = jest.spyOn(
       globalThis.window,

src/core/tests/onlineManager.test.tsx

@@ -67,6 +67,19 @@ describe('onlineManager', () => {
     restoreIsServer()
   })
 
+  test('cleanup should still be undefined if window.addEventListener is not defined', async () => {
+    const { addEventListener } = globalThis.window
+
+    // @ts-expect-error
+    globalThis.window.addEventListener = undefined
+
+    const unsubscribe = onlineManager.subscribe(() => undefined)
+    expect(onlineManager['cleanup']).toBeUndefined()
+
+    unsubscribe()
+    globalThis.window.addEventListener = addEventListener
+  })
+
   test('it should replace default window listener when a new event listener is set', async () => {
     const addEventListenerSpy = jest.spyOn(
       globalThis.window,