使用重定向进行 Expo Router 身份验证

import { useContext, createContext, type PropsWithChildren } from 'react';
import { useStorageState } from './useStorageState';

const AuthContext = createContext<{
  signIn: () => void;
  signOut: () => void;
  session?: string | null;
  isLoading: boolean;
}>({
  signIn: () => null,
  signOut: () => null,
  session: null,
  isLoading: false,
});

// 此 hook 可用于访问用户信息。
export function useSession() {
  const value = useContext(AuthContext);
  if (!value) {
    throw new Error('useSession 必须被 <SessionProvider /> 包装');
  }

  return value;
}

export function SessionProvider({ children }: PropsWithChildren) {
  const [[isLoading, session], setSession] = useStorageState('session');

  return (
    <AuthContext.Provider
      value={{
        signIn: () => {
          // 在此处理登录逻辑
          setSession('xxx');
        },
        signOut: () => {
          setSession(null);
        },
        session,
        isLoading,
      }}>
      {children}
    </AuthContext.Provider>
  );
}

import  { useEffect, useCallback, useReducer } from 'react';
import * as SecureStore from 'expo-secure-store';
import { Platform } from 'react-native';

type UseStateHook<T> = [[boolean, T | null], (value: T | null) => void];

function useAsyncState<T>(
  initialValue: [boolean, T | null] = [true, null],
): UseStateHook<T> {
  return useReducer(
    (state: [boolean, T | null], action: T | null = null): [boolean, T | null] => [false, action],
    initialValue
  ) as UseStateHook<T>;
}

export async function setStorageItemAsync(key: string, value: string | null) {
  if (process.env.EXPO_OS === 'web') {
    if (value === null) {
      localStorage.removeItem(key);
    } else {
      localStorage.setItem(key, value);
    }
  } else {
    if (value == null) {
      await SecureStore.deleteItemAsync(key);
    } else {
      await SecureStore.setItemAsync(key, value);
    }
  }
}

export function useStorageState(key: string): UseStateHook<string> {
  // 公共
  const [state, setState] = useAsyncState<string>();

  // 获取
  useEffect(() => {
    if (Platform.OS === 'web') {
      try {
        if (typeof localStorage !== 'undefined') {
          setState(localStorage.getItem(key));
        }
      } catch (e) {
        console.error('Local storage is unavailable:', e);
      }
    } else {
      SecureStore.getItemAsync(key).then((value: string | null) => {
        setState(value);
      });
    }
  }, [key]);

  // 设置
  const setValue = useCallback(
    (value: string | null) => {
      setState(value);
      setStorageItemAsync(key, value);
    },
    [key]
  );

  return [state, setValue];
}