refactor(react-native): bypass proxy once client is initialized

Author: yousif-bugsnag

packages/platforms/react-native/lib/client.ts

@@ -19,22 +19,28 @@ export function registerClient<C extends ReactNativeConfiguration = ReactNativeC
 const clock = createClock(performance)
 const appStartTime = clock.now()
 
-// Proxy wrapper that provides lazy initialization of the BugsnagPerformance client.
-// How it works:
-// 1. If registerClient() was called (e.g., by Expo), the proxy delegates to that pre-configured instance
-// 2. Otherwise, on first property access, it creates a default client via createReactNativeClient()
-// 3. All subsequent accesses use the same singleton instance, ensuring one client per app
-// The Proxy intercepts all property accesses and forwards them to the actual client instance.
+// Proxy wrapper for lazy initialization of the BugsnagPerformance client.
+// On first property access:
+// - Uses pre-configured client from registerClient() if available, otherwise creates a new client
+// - Copies all client properties to the proxy target and removes the get trap
+// - All subsequent accesses go directly to the target, bypassing the proxy for optimal performance
 const client = new Proxy({} as BugsnagPerformance<ReactNativeConfiguration, PlatformExtensions>, {
-  get (_target, prop) {
+  get (target, prop) {
     // React uses the $$typeof property to identify React elements - we return undefined
     // to avoid triggering client creation during React's internal type checking
     if (prop === '$$typeof') return undefined
 
+    // initialize the client instance here if it hasn't already been set via registerClient()
     if (!clientInstance) {
       clientInstance = createReactNativeClient({ appStartTime, clock })
     }
+
+    // Now that the client has been initialized, we can add all its properties to the proxy target
+    // and remove the get trap in order to bypass the proxy for future accesses
     const client = clientInstance as BugsnagPerformance<ReactNativeConfiguration, PlatformExtensions>
+    Object.defineProperties(target, Object.getOwnPropertyDescriptors(client))
+    delete this.get
+
     return client[prop as keyof typeof client]
   }
 })

packages/platforms/react-native/tests/client.test.ts

@@ -2,6 +2,7 @@
 import type { ReactNativeConfiguration } from '../lib/config'
 import type { BugsnagPerformance } from '@bugsnag/core-performance'
 import type { PlatformExtensions } from '../lib/platform-extensions'
+import { IncrementingClock } from '@bugsnag/js-performance-test-utilities'
 
 let client: BugsnagPerformance<ReactNativeConfiguration, PlatformExtensions>
 
@@ -20,3 +21,51 @@ describe('Default React Native Client', () => {
     expect(client.attach).toBeDefined()
   })
 })
+
+describe('singleton behavior', () => {
+  beforeEach(() => {
+    // Reset modules to clear the singleton
+    jest.resetModules()
+  })
+
+  it('should allow custom clients to be set and used as default', () => {
+    const { registerClient } = require('../lib/client')
+    const { createReactNativeClient } = require('../lib/create-client')
+    const clock = new IncrementingClock()
+
+    // Import the default client
+    const defaultClient = require('../lib/client').default
+
+    // Create and register a custom client
+    const testClient = createReactNativeClient({ clock })
+    registerClient(testClient)
+
+    // The default should proxy to the test client
+    expect(defaultClient.start).toBe(testClient.start)
+    expect(defaultClient.startSpan).toBe(testClient.startSpan)
+  })
+
+  it('should create default client if none is set', () => {
+    const createReactNativeClient = jest.spyOn(require('../lib/create-client'), 'createReactNativeClient')
+    const client = require('../lib/client')
+    const defaultClient = client.default
+
+    // createReactNativeClient should be called on first access
+    expect(createReactNativeClient).not.toHaveBeenCalled()
+    expect(defaultClient.start).toBeDefined()
+    expect(defaultClient.startSpan).toBeDefined()
+    expect(createReactNativeClient).toHaveBeenCalledTimes(1)
+  })
+
+  it('should correctly handle getter properties after trap removal', () => {
+    const defaultClient = require('../lib/client').default
+
+    // starting a span will trigger trap removal
+    const span = defaultClient.startSpan('test-span')
+
+    // Getters such as currentSpanContext should return the current value
+    // as opposed to the value at the time of first access
+    expect(defaultClient.currentSpanContext).toBeDefined()
+    expect(defaultClient.currentSpanContext.id).toBe(span.id)
+  })
+})

packages/platforms/react-native/tests/create-client.test.ts

@@ -1,4 +1,3 @@
-/* eslint-disable @typescript-eslint/no-var-requires */
 import {
   InMemoryDelivery,
   IncrementingClock,
@@ -145,40 +144,4 @@ describe('createReactNativeClient', () => {
       expect(client.attach).toBeUndefined()
     })
   })
-
-  describe('singleton behavior', () => {
-    beforeEach(() => {
-      // Reset modules to clear the singleton
-      jest.resetModules()
-    })
-
-    it('should allow custom clients to be set and used as default', () => {
-      const { registerClient } = require('../lib/client')
-      const { createReactNativeClient } = require('../lib/create-client')
-      const clock = new IncrementingClock()
-
-      // Import the default client
-      const defaultClient = require('../lib/client').default
-
-      // Create and register a custom client
-      const testClient = createReactNativeClient({ clock })
-      registerClient(testClient)
-
-      // The default should proxy to the test client
-      expect(defaultClient.start).toBe(testClient.start)
-      expect(defaultClient.startSpan).toBe(testClient.startSpan)
-    })
-
-    it('should create default client if none is set', () => {
-      const createReactNativeClient = jest.spyOn(require('../lib/create-client'), 'createReactNativeClient')
-      const client = require('../lib/client')
-      const defaultClient = client.default
-
-      // createReactNativeClient should be called on first access
-      expect(createReactNativeClient).not.toHaveBeenCalled()
-      expect(defaultClient.start).toBeDefined()
-      expect(defaultClient.startSpan).toBeDefined()
-      expect(createReactNativeClient).toHaveBeenCalledTimes(1)
-    })
-  })
 })