feat(clerk-expo): Introduce support for LocalAuth with LocalCredentials

.changeset/rude-poets-beam.md

@@ -0,0 +1,5 @@
+---
+"@clerk/clerk-expo": minor
+---
+
+Introduce support for LocalAuthentication with `useLocalCredentials`.

packages/expo/package.json

@@ -65,17 +65,29 @@
     "@types/react": "*",
     "@types/react-dom": "*",
     "expo-auth-session": "^5.4.0",
+    "expo-local-authentication": "^13.5.0",
+    "expo-secure-store": "^12.4.0",
     "expo-web-browser": "^12.8.2",
     "react-native": "^0.73.9",
     "typescript": "*"
   },
   "peerDependencies": {
     "expo-auth-session": ">=5",
+    "expo-local-authentication": ">=13.5.0",
+    "expo-secure-store": ">=12.4.0",
     "expo-web-browser": ">=12.5.0",
     "react-native": ">=0.73",
     "react": ">=18",
     "react-dom": ">=18"
   },
+  "peerDependenciesMeta": {
+    "expo-secure-store": {
+      "optional": true
+    },
+    "expo-local-authentication": {
+      "optional": true
+    }
+  },
   "engines": {
     "node": ">=18.17.0"
   },

packages/expo/src/hooks/index.ts

@@ -12,3 +12,4 @@ export {
 } from '@clerk/clerk-react';
 
 export * from './useOAuth';
+export * from './useLocalCredentials';

packages/expo/src/hooks/useLocalCredentials/index.tsx

@@ -0,0 +1 @@
+export { useLocalCredentials } from './useLocalCredentials';

packages/expo/src/hooks/useLocalCredentials/shared.ts

@@ -0,0 +1,31 @@
+import type { SignInResource } from '@clerk/types';
+
+type LocalCredentials = {
+  identifier?: string;
+  password: string;
+};
+
+type BiometricType = 'fingerprint' | 'face-recognition';
+
+type LocalCredentialsReturn = {
+  setCredentials: (creds: LocalCredentials) => Promise<void>;
+  hasCredentials: boolean;
+  userOwnsCredentials: boolean | null;
+  clearCredentials: () => Promise<void>;
+  authenticate: () => Promise<SignInResource>;
+  biometryType: BiometricType | null;
+};
+
+const LocalCredentialsInitValues: LocalCredentialsReturn = {
+  setCredentials: () => Promise.resolve(),
+  hasCredentials: false,
+  userOwnsCredentials: null,
+  clearCredentials: () => Promise.resolve(),
+  // @ts-expect-error Initial value cannot return what the type expects
+  authenticate: () => Promise.resolve({}),
+  biometryType: null,
+};
+
+export { LocalCredentialsInitValues };
+
+export type { LocalCredentials, BiometricType, LocalCredentialsReturn };

packages/expo/src/hooks/useLocalCredentials/useLocalCredentials.ts

@@ -0,0 +1,183 @@
+import { useClerk, useSignIn, useUser } from '@clerk/clerk-react';
+import { AuthenticationType, isEnrolledAsync, supportedAuthenticationTypesAsync } from 'expo-local-authentication';
+import {
+  deleteItemAsync,
+  getItem,
+  getItemAsync,
+  setItemAsync,
+  WHEN_PASSCODE_SET_THIS_DEVICE_ONLY,
+} from 'expo-secure-store';
+import { useEffect, useState } from 'react';
+
+import { errorThrower } from '../../utils';
+import type { BiometricType, LocalCredentials, LocalCredentialsReturn } from './shared';
+
+const useEnrolledBiometric = () => {
+  const [isEnrolled, setIsEnrolled] = useState(false);
+
+  useEffect(() => {
+    let ignore = false;
+
+    void isEnrolledAsync().then(res => {
+      if (ignore) {
+        return;
+      }
+      setIsEnrolled(res);
+    });
+
+    return () => {
+      ignore = true;
+    };
+  }, []);
+
+  return isEnrolled;
+};
+
+const useAuthenticationType = () => {
+  const [authenticationType, setAuthenticationType] = useState<BiometricType | null>(null);
+
+  useEffect(() => {
+    let ignore = false;
+
+    void supportedAuthenticationTypesAsync().then(numericTypes => {
+      if (ignore) {
+        return;
+      }
+      if (numericTypes.length === 0) {
+        return;
+      }
+
+      if (numericTypes.includes(AuthenticationType.FINGERPRINT)) {
+        setAuthenticationType('fingerprint');
+      } else {
+        setAuthenticationType('face-recognition');
+      }
+    });
+
+    return () => {
+      ignore = true;
+    };
+  }, []);
+
+  return authenticationType;
+};
+
+const useUserOwnsCredentials = ({ storeKey }: { storeKey: string }) => {
+  const { user } = useUser();
+  const [userOwnsCredentials, setUserOwnsCredentials] = useState(false);
+
+  const getUserCredentials = (storedIdentifier: string | null): boolean => {
+    if (!user || !storedIdentifier) {
+      return false;
+    }
+
+    const identifiers = [
+      user.emailAddresses.map(e => e.emailAddress),
+      user.phoneNumbers.map(p => p.phoneNumber),
+    ].flat();
+
+    if (user.username) {
+      identifiers.push(user.username);
+    }
+    return identifiers.includes(storedIdentifier);
+  };
+
+  useEffect(() => {
+    let ignore = false;
+    getItemAsync(storeKey)
+      .catch(() => null)
+      .then(res => {
+        if (ignore) {
+          return;
+        }
+        setUserOwnsCredentials(getUserCredentials(res));
+      });
+
+    return () => {
+      ignore = true;
+    };
+  }, [storeKey, user]);
+
+  return [userOwnsCredentials, setUserOwnsCredentials] as const;
+};
+
+export const useLocalCredentials = (): LocalCredentialsReturn => {
+  const { isLoaded, signIn } = useSignIn();
+  const { publishableKey } = useClerk();
+
+  const key = `__clerk_local_auth_${publishableKey}_identifier`;
+  const pkey = `__clerk_local_auth_${publishableKey}_password`;
+  const [hasLocalAuthCredentials, setHasLocalAuthCredentials] = useState(!!getItem(key));
+  const [userOwnsCredentials, setUserOwnsCredentials] = useUserOwnsCredentials({ storeKey: key });
+  const hasEnrolledBiometric = useEnrolledBiometric();
+  const authenticationType = useAuthenticationType();
+
+  const biometryType = hasEnrolledBiometric ? authenticationType : null;
+
+  const setCredentials = async (creds: LocalCredentials) => {
+    if (!(await isEnrolledAsync())) {
+      return;
+    }
+
+    if (creds.identifier && !creds.password) {
+      return errorThrower.throw(
+        `useLocalCredentials: setCredentials() A password is required when specifying an identifier.`,
+      );
+    }
+
+    if (creds.identifier) {
+      await setItemAsync(key, creds.identifier);
+    }
+
+    const storedIdentifier = await getItemAsync(key).catch(() => null);
+
+    if (!storedIdentifier) {
+      return errorThrower.throw(
+        `useLocalCredentials: setCredentials() an identifier should already be set in order to update its password.`,
+      );
+    }
+
+    setHasLocalAuthCredentials(true);
+    await setItemAsync(pkey, creds.password, {
+      keychainAccessible: WHEN_PASSCODE_SET_THIS_DEVICE_ONLY,
+      requireAuthentication: true,
+    });
+  };
+
+  const clearCredentials = async () => {
+    await Promise.all([deleteItemAsync(key), deleteItemAsync(pkey)]);
+    setHasLocalAuthCredentials(false);
+    setUserOwnsCredentials(false);
+  };
+
+  const authenticate = async () => {
+    if (!isLoaded) {
+      return errorThrower.throw(
+        `useLocalCredentials: authenticate() Clerk has not loaded yet. Wait for clerk to load before calling this function`,
+      );
+    }
+    const identifier = await getItemAsync(key).catch(() => null);
+    if (!identifier) {
+      return errorThrower.throw(`useLocalCredentials: authenticate() the identifier could not be found`);
+    }
+    const password = await getItemAsync(pkey).catch(() => null);
+
+    if (!password) {
+      return errorThrower.throw(`useLocalCredentials: authenticate() cannot retrieve a password for that identifier`);
+    }
+
+    return signIn.create({
+      strategy: 'password',
+      identifier,
+      password,
+    });
+  };
+  return {
+    setCredentials,
+    hasCredentials: hasLocalAuthCredentials,
+    userOwnsCredentials,
+    clearCredentials,
+    authenticate,
+    biometryType,
+  };
+};

packages/expo/src/hooks/useLocalCredentials/useLocalCredentials.web.ts

@@ -0,0 +1,6 @@
+import type { LocalCredentialsReturn } from './shared';
+import { LocalCredentialsInitValues } from './shared';
+
+export const useLocalCredentials = (): LocalCredentialsReturn => {
+  return LocalCredentialsInitValues;
+};