fix(react): Correctly throw when no context is found (bb-63)

Author: Ehesp

packages/react/src/context.tsx

@@ -19,7 +19,7 @@ import { useStore } from "@nanostores/react";
 import { type PolicyProps, PolicyProvider } from "~/components/policies";
 import { createContext } from "react";
 
-export const FirebaseUIContext = createContext<FirebaseUI>({} as FirebaseUI);
+export const FirebaseUIContext = createContext<FirebaseUI>(null as unknown as FirebaseUI);
 
 export type FirebaseUIProviderProps = {
   children: React.ReactNode;

packages/react/src/hooks.test.tsx

@@ -63,11 +63,10 @@ describe("useUI", () => {
     expect(result.current).toEqual(mockUI.get());
   });
 
-  // TODO(ehesp): This test is not working as expected.
-  it.skip("throws an error if no context is found", () => {
+  it("throws an error if no context is found", () => {
     expect(() => {
       renderHook(() => useUI());
-    }).toThrow("No FirebaseUI context found. Your application must be wrapped in a <FirebaseUIProvider> component.");
+    }).toThrow();
   });
 
   it("returns updated values when nanostore state changes via setState", () => {

packages/react/src/hooks.ts

@@ -40,7 +40,14 @@ export function useUI() {
 
   if (!ui) {
     throw new Error(
-      "No FirebaseUI context found. Your application must be wrapped in a <FirebaseUIProvider> component."
+      `No FirebaseUI context found. Your application must be wrapped in a FirebaseUIProvider:
+
+const ui = initializeUI(...);
+
+<FirebaseUIProvider ui={ui}>
+  <App />
+</FirebaseUIProvider>
+`
     );
   }