ahooks封装cookie localStorage sessionStorage方法

const [state, setState] = useState<State>(() => {
  // 假如有值，则直接返回
  const cookieValue = Cookies.get(cookieKey);

  if (isString(cookieValue)) return cookieValue;
  // 定义 Cookie 默认值，但不同步到本地 Cookie
  // 可以自定义默认值
  if (isFunction(options.defaultValue)) {
    return options.defaultValue();
  }

  return options.defaultValue;
});

// 设置 Cookie 值
const updateState = useMemoizedFn(
  (
    newValue: State | ((prevState: State) => State),
    newOptions: Cookies.CookieAttributes = {},
  ) => {
    const { defaultValue, ...restOptions } = { ...options, ...newOptions };
    setState((prevState) => {
      const value = isFunction(newValue) ? newValue(prevState) : newValue;
      // 值为 undefined 的时候，清除 cookie
      if (value === undefined) {
        Cookies.remove(cookieKey);
      } else {
        Cookies.set(cookieKey, value, restOptions);
      }
      return value;
    });
  },
);

return [state, updateState] as const;

import { createUseStorageState } from '../createUseStorageState';
import isBrowser from '../utils/isBrowser';

const useLocalStorageState = createUseStorageState(() => (isBrowser ? localStorage : undefined));

export default useLocalStorageState;

export function createUseStorageState(getStorage: () => Storage | undefined) {
  function useStorageState<T>(key: string, options?: Options<T>) {
    let storage: Storage | undefined;
    // https://GitHub.com/alibaba/hooks/issues/800
    try {
      storage = getStorage();
    } catch (err) {
      console.error(err);
    }
    // 代码在后面讲解
}

// 自定义序列化方法
const serializer = (value: T) => {
  if (options?.serializer) {
    return options?.serializer(value);
  }
  return JSON.stringify(value);
};

// 自定义反序列化方法
const deserializer = (value: string) => {
  if (options?.deserializer) {
    return options?.deserializer(value);
  }
  return JSON.parse(value);
};

function getStoredValue() {
  try {
    const raw = storage?.getItem(key);
    if (raw) {
      return deserializer(raw);
    }
  } catch (e) {
    console.error(e);
  }
  // 默认值
  if (isFunction(options?.defaultValue)) {
    return options?.defaultValue();
  }
  return options?.defaultValue;
}

const [state, setState] = useState<T | undefined>(() => getStoredValue());

// 当 key 更新的时候执行
useUpdateEffect(() => {
  setState(getStoredValue());
}, [key]);

// 设置 State
const updateState = (value?: T | IFuncUpdater<T>) => {
  // 如果是 undefined，则移除选项
  if (isUndef(value)) {
    setState(undefined);
    storage?.removeItem(key);
    // 如果是function，则用来传入 state，并返回结果
  } else if (isFunction(value)) {
    const currentState = value(state);
    try {
      setState(currentState);
      storage?.setItem(key, serializer(currentState));
    } catch (e) {
      console.error(e);
    }
  } else {
    // 设置值
    try {
      setState(value);
      storage?.setItem(key, serializer(value));
    } catch (e) {
      console.error(e);
    }
  }
};