keycloak-scim/apps/admin-ui/src/utils/useStoredState.ts
2023-02-08 13:08:46 +01:00

38 lines
1.9 KiB
TypeScript

import { Dispatch, useCallback, useMemo } from "react";
import { useStorageItem } from "./useStorageItem";
/**
* A hook that acts similarly to React's `useState()`, but persists the state using [Web Storage API](https://developer.mozilla.org/en-US/docs/Web/API/Web_Storage_API).
* Automatically updates the value when modified in the context of another document (such as an open tab) trough the [`storage`](https://developer.mozilla.org/en-US/docs/Web/API/Window/storage_event) event.
*
* The value is serialized as [JSON](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON) and therefore the value provided must be serializable as such.
* Because the value is always serialized it will never be referentially equal to originally provided value.
*
* @param storageArea The storage area to target, must implement the [`Storage`](https://developer.mozilla.org/en-US/docs/Web/API/Storage) interface (such as [`localStorage`](https://developer.mozilla.org/en-US/docs/Web/API/Window/localStorage) and [`sessionStorage`](https://developer.mozilla.org/en-US/docs/Web/API/Window/sessionStorage)).
* @param keyName The key of the item to get from storage, same as passed to [`Storage.getItem()`](https://developer.mozilla.org/en-US/docs/Web/API/Storage/getItem)
* @param defaultValue The default value to fall back to in case no stored value was retrieved (must be serializable as JSON).
*/
export function useStoredState<S>(
storageArea: Storage,
keyName: string,
defaultValue: S
): [S, Dispatch<S>] {
const defaultValueSerialized = useMemo(
() => JSON.stringify(defaultValue),
[defaultValue]
);
const [storedValue, setStoredValue] = useStorageItem(
storageArea,
keyName,
defaultValueSerialized
);
const value = useMemo<S>(() => JSON.parse(storedValue), [storedValue]);
const setValue = useCallback(
(value: S) => setStoredValue(JSON.stringify(value)),
[]
);
return [value, setValue];
}