🐛 [RUMF-1449] fix Zone support when __symbol__ is missing

packages/core/src/tools/getZoneJsOriginalValue.spec.ts

@@ -1,5 +1,6 @@
 import { stubZoneJs } from '../../test/stubZoneJs'
 
+import type { BrowserWindowWithZoneJs } from './getZoneJsOriginalValue'
 import { getZoneJsOriginalValue } from './getZoneJsOriginalValue'
 import { noop } from './utils'
 
@@ -22,11 +23,17 @@ describe('getZoneJsOriginalValue', () => {
     expect(getZoneJsOriginalValue(object, 'name')).toBe(originalValue)
   })
 
-  it("returns undefined if Zone is defined but didn't patch that method", () => {
+  it("returns the original value if Zone is defined but didn't patch that method", () => {
     zoneJsStub = stubZoneJs()
     expect(getZoneJsOriginalValue(object, 'name')).toBe(originalValue)
   })
 
+  it('returns the original value if Zone is defined but does not define the __symbol__ function', () => {
+    zoneJsStub = stubZoneJs()
+    delete (window as BrowserWindowWithZoneJs).Zone!.__symbol__
+    expect(getZoneJsOriginalValue(object, 'name')).toBe(originalValue)
+  })
+
   it('returns the original value if Zone did patch the method', () => {
     zoneJsStub = stubZoneJs()
     zoneJsStub.replaceProperty(object, 'name', noop)

packages/core/src/tools/getZoneJsOriginalValue.ts

@@ -1,6 +1,9 @@
 export interface BrowserWindowWithZoneJs extends Window {
   Zone?: {
-    __symbol__: (name: string) => string
+    // All Zone.js versions expose the __symbol__ method, but we observed that some website have a
+    // 'Zone' global variable unrelated to Zone.js, so let's consider this method optional
+    // nonetheless.
+    __symbol__?: (name: string) => string
   }
 }
 
@@ -23,7 +26,7 @@ export function getZoneJsOriginalValue<Target, Name extends keyof Target & strin
 ): Target[Name] {
   const browserWindow = window as BrowserWindowWithZoneJs
   let original: Target[Name] | undefined
-  if (browserWindow.Zone) {
+  if (browserWindow.Zone && typeof browserWindow.Zone.__symbol__ === 'function') {
     original = (target as any)[browserWindow.Zone.__symbol__(name)]
   }
   if (!original) {