chore: exclude test files from TypeScript build

Fixes FORMBRICKS-HJ

- Add defensive polyfill for window.webkit.messageHandlers
- Prevents TypeError when accessing unregistered handlers in Facebook's iOS in-app browser
- Uses Proxy to safely intercept access and return no-op postMessage for missing handlers
- Solves issue with Cal.com embed trying to use native WebKit messaging in unsupported environments

packages/surveys/src/index.ts

@@ -6,6 +6,36 @@ import { FILE_PICK_EVENT } from "@/lib/constants";
 import { getI18nLanguage } from "@/lib/i18n-utils";
 import { addCustomThemeToDom, addStylesToDom, setStyleNonce } from "@/lib/styles";
 
+// Polyfill for webkit messageHandlers to prevent errors in browsers that don't fully support it
+// (e.g., Facebook's iOS in-app browser). This prevents TypeError when accessing unregistered handlers.
+if (typeof window !== "undefined") {
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any -- WebKit types are not standard
+  const win = window as any;
+
+  if (win.webkit?.messageHandlers) {
+    const originalMessageHandlers = win.webkit.messageHandlers;
+
+    // Create a Proxy that safely handles access to potentially undefined message handlers
+    win.webkit.messageHandlers = new Proxy(originalMessageHandlers, {
+      get(target, prop) {
+        const handler = target[prop as keyof typeof target];
+
+        // If the handler doesn't exist, return a safe mock object with a no-op postMessage
+        if (!handler) {
+          return {
+            postMessage: () => {
+              // Silently ignore - the message handler is not registered in this environment
+              console.debug(`WebKit message handler "${String(prop)}" is not available in this environment`);
+            },
+          };
+        }
+
+        return handler;
+      },
+    });
+  }
+}
+
 export const renderSurveyInline = (props: SurveyContainerProps) => {
   const inlineProps: SurveyContainerProps = {
     ...props,

packages/surveys/src/lib/webkit-polyfill.test.ts

@@ -0,0 +1,126 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+
+describe("WebKit messageHandlers polyfill", () => {
+  let originalWebkit: any;
+  let consoleDebugSpy: any;
+
+  beforeEach(() => {
+    // Save the original webkit object if it exists
+    originalWebkit = (window as any).webkit;
+    consoleDebugSpy = vi.spyOn(console, "debug").mockImplementation(() => {});
+  });
+
+  afterEach(() => {
+    // Restore the original webkit object
+    if (originalWebkit) {
+      (window as any).webkit = originalWebkit;
+    } else {
+      delete (window as any).webkit;
+    }
+    consoleDebugSpy.mockRestore();
+  });
+
+  it("should not throw when accessing undefined messageHandlers", () => {
+    // Setup: Create a webkit object with messageHandlers but no specific handlers
+    (window as any).webkit = {
+      messageHandlers: {},
+    };
+
+    // Apply the polyfill logic
+    const originalMessageHandlers = (window as any).webkit.messageHandlers;
+    (window as any).webkit.messageHandlers = new Proxy(originalMessageHandlers, {
+      get(target, prop) {
+        const handler = target[prop as keyof typeof target];
+
+        if (!handler) {
+          return {
+            postMessage: () => {
+              console.debug(`WebKit message handler "${String(prop)}" is not available in this environment`);
+            },
+          };
+        }
+
+        return handler;
+      },
+    });
+
+    // Test: Accessing an undefined handler should not throw
+    expect(() => {
+      (window as any).webkit.messageHandlers.undefinedHandler.postMessage("test");
+    }).not.toThrow();
+
+    // Verify console.debug was called
+    expect(consoleDebugSpy).toHaveBeenCalledWith(
+      'WebKit message handler "undefinedHandler" is not available in this environment'
+    );
+  });
+
+  it("should still work with existing handlers", () => {
+    // Setup: Create a webkit object with a real handler
+    const mockPostMessage = vi.fn();
+    (window as any).webkit = {
+      messageHandlers: {
+        existingHandler: {
+          postMessage: mockPostMessage,
+        },
+      },
+    };
+
+    // Apply the polyfill logic
+    const originalMessageHandlers = (window as any).webkit.messageHandlers;
+    (window as any).webkit.messageHandlers = new Proxy(originalMessageHandlers, {
+      get(target, prop) {
+        const handler = target[prop as keyof typeof target];
+
+        if (!handler) {
+          return {
+            postMessage: () => {
+              console.debug(`WebKit message handler "${String(prop)}" is not available in this environment`);
+            },
+          };
+        }
+
+        return handler;
+      },
+    });
+
+    // Test: Existing handler should still work
+    (window as any).webkit.messageHandlers.existingHandler.postMessage("test message");
+
+    expect(mockPostMessage).toHaveBeenCalledWith("test message");
+  });
+
+  it("should handle multiple undefined handlers", () => {
+    // Setup
+    (window as any).webkit = {
+      messageHandlers: {},
+    };
+
+    // Apply the polyfill logic
+    const originalMessageHandlers = (window as any).webkit.messageHandlers;
+    (window as any).webkit.messageHandlers = new Proxy(originalMessageHandlers, {
+      get(target, prop) {
+        const handler = target[prop as keyof typeof target];
+
+        if (!handler) {
+          return {
+            postMessage: () => {
+              console.debug(`WebKit message handler "${String(prop)}" is not available in this environment`);
+            },
+          };
+        }
+
+        return handler;
+      },
+    });
+
+    // Test: Multiple undefined handlers should not throw
+    expect(() => {
+      (window as any).webkit.messageHandlers.handler1.postMessage("test1");
+      (window as any).webkit.messageHandlers.handler2.postMessage("test2");
+      (window as any).webkit.messageHandlers.handler3.postMessage("test3");
+    }).not.toThrow();
+
+    expect(consoleDebugSpy).toHaveBeenCalledTimes(3);
+  });
+});

packages/surveys/tsconfig.json

@@ -12,6 +12,7 @@
     },
     "resolveJsonModule": true
   },
+  "exclude": ["**/*.test.ts", "**/*.test.tsx"],
   "extends": "@formbricks/config-typescript/js-library.json",
   "include": ["src", "../types/surveys.d.ts"]
 }