feat(app-check): add useAppCheckToken (#158)

.gitignore

@@ -5,6 +5,7 @@
 /test-results/
 
 # modules
+/app-check/
 /auth/
 /database/
 /firestore/

README.md

@@ -38,6 +38,8 @@ If you previously used [`react-firebase-hooks`](https://www.npmjs.com/package/re
 
 This library consists of 4 modules with many hooks:
 
+-   [`app-check`](#AppCheck)
+    -   [`useAppCheckToken`](#useAppCheckToken)
 -   [`auth`](#Auth)
     -   [`useAuthIdToken`](#useAuthIdToken)
     -   [`useAuthIdTokenResult`](#useAuthIdTokenResult)
@@ -67,6 +69,30 @@ This library consists of 4 modules with many hooks:
 
 All hooks can be imported from `react-firehooks` directly or via `react-firehooks/<module>` to improve tree-shaking and bundle size.
 
+### App Check
+
+```javascript
+import { ... } from 'react-firehooks/app-check';
+```
+
+#### useAuthState
+
+Returns and updates the current App Check token
+
+```javascript
+const [user, loading, error] = useAppCheckToken(auth);
+```
+
+Params:
+
+-   `appCheck`: Firebase App Check instance
+
+Returns:
+
+-   `value`: App Check token; `undefined` if the token is currently being fetched, or an error occurred
+-   `loading`: `true` while fetching the token; `false` if the token was fetched successfully or an error occurred
+-   `error`: `undefined` if no error occurred
+
 ### Auth
 
 ```javascript

scripts/create-modules.js

@@ -1,6 +1,6 @@
 import fs from "fs";
 
-const modules = ["auth", "database", "firestore", "messaging", "storage"];
+const modules = ["app-check", "auth", "database", "firestore", "messaging", "storage"];
 for (const module of modules) {
     const packageJson = {
         main: `../lib/${module}/index.js`,

src/app-check/index.ts

@@ -0,0 +1 @@
+export * from "./useAppCheckToken.js";

src/app-check/useAppCheckToken.ts

@@ -0,0 +1,25 @@
+import { AppCheck, AppCheckTokenResult, onTokenChanged } from "firebase/app-check";
+import { useCallback } from "react";
+import { ValueHookResult } from "../common/index.js";
+import { useListen, UseListenOnChange } from "../internal/useListen.js";
+import { LoadingState } from "../internal/useLoadingValue.js";
+
+export type UseAppCheckToken = ValueHookResult<AppCheckTokenResult | null, Error>;
+
+/**
+ * Returns and updates the current App Check token
+ *
+ * @param {AppCheck} appCheck Firebase App Check instance
+ * @returns {UseAppCheckToken} App Check token, loading state, and error
+ * * value: App Check token; `undefined` if token is currently being fetched, or an error occurred
+ * * loading: `true` while fetching the token; `false` if the token was fetched successfully or an error occurred
+ * * error: `undefined` if no error occurred
+ */
+export function useAppCheckToken(appCheck: AppCheck): UseAppCheckToken {
+    const onChange: UseListenOnChange<AppCheckTokenResult | null, Error, AppCheck> = useCallback(
+        (stableAppCheck, next, error) => onTokenChanged(stableAppCheck, next, error),
+        []
+    );
+
+    return useListen(appCheck, onChange, () => true, LoadingState);
+}

src/index.ts

@@ -1,3 +1,4 @@
+export * from "./app-check/index.js";
 export * from "./auth/index.js";
 export * from "./common/index.js";
 export * from "./database/index.js";