fix: only wrap once when patching (#1245)

* fix: only wrap once when patching

* only init once

* fix

* we might actually want to wrap twice e.g. trace headers

src/__tests__/extensions/replay/rrweb-plugins/patch.test.ts

@@ -0,0 +1,15 @@
+import { patch } from '../../../../extensions/replay/rrweb-plugins/patch'
+
+const fakeWindow = {
+    fakeFetch: () => {},
+}
+
+// JS-DOM doesn't have fetch and its fake XHR doesn't work with our patch,
+// so we can't test them directly
+describe('patch', () => {
+    it('marks a function as wrapped', () => {
+        patch(fakeWindow, 'fakeFetch', () => () => {})
+        // eslint-disable-next-line compat/compat
+        expect((fakeWindow.fakeFetch as any).__posthog_wrapped__).toBe(true)
+    })
+})

src/loader-recorder.ts

@@ -483,6 +483,7 @@ function initFetchObserver(
     }
 }
 
+let initialisedHandler: listenerHandler | null = null
 function initNetworkObserver(
     callback: networkCallback,
     win: IWindow, // top window or in an iframe
@@ -493,6 +494,14 @@ function initNetworkObserver(
             //
         }
     }
+
+    if (initialisedHandler) {
+        logger.warn('Network observer already initialised, doing nothing')
+        return () => {
+            // the first caller should already have this handler and will be responsible for teardown
+        }
+    }
+
     const networkOptions = (
         options ? Object.assign({}, defaultNetworkOptions, options) : defaultNetworkOptions
     ) as Required<NetworkRecordOptions>
@@ -520,11 +529,12 @@ function initNetworkObserver(
         fetchObserver = initFetchObserver(cb, win, networkOptions)
     }
 
-    return () => {
+    initialisedHandler = () => {
         performanceObserver()
         xhrObserver()
         fetchObserver()
     }
+    return initialisedHandler
 }
 
 // use the plugin name so that when this functionality is adopted into rrweb