`tsx
// main.tsx
import { observer } from 'mobx-react-lite';
import { useEffect } from 'react';
import { usePersistentStore } from './store-setup';

const Main = observer(() => {
const { name, age, isAdult, hydrated, hydrate } = usePersistentStore();

useEffect(() => {
hydrate();
}, []);

if (!hydrated) {
return

Loading...

export default Main;
`

Custom Storage Backend

The above example uses the default storage. You can use any storage you want by passing the storage object to the factory.

Here is an example using react-native-mmkv as the storage.

`ts
import { MMKV } from 'react-native-mmkv';

const mmkv = new MMKV();

const setItem = (key: string, value: any) => mmkv.set(key, JSON.stringify(value));

const getItem = (key: string) => {
const value = mmkv.getString(key);
if (value) {
return JSON.parse(value);
}
return null;
};

const removeItem = (key: string) => mmkv.delete(key);

const storage = {
setItem,
getItem,
removeItem,
};

export const [PersistentStoreProvider, usePersistentStore] = createPersistentStore(
PersistentStore,
storage,
{
name: 'Test User',
age: 19,
premium: false,
hydrated: false,
},
{
hydrated: false,
},
{
hydrated: false,
}
);
`

API

$3

#### Type Definition

`ts
export interface StorageOptions {
setItem: (key: string, value: any) => Promise | void;
getItem: (key: string) => Promise | any | null;
removeItem: (key: string) => Promise | void;
}

interface PersistentStoreOptions {
storageKey: string;
writeDelay: number;
logging: boolean;
devtool: boolean;
onHydrate?: (store: Instance) => void;
}
const createPersistentStore: (
store: T,
storage: StorageOptions,
init: SnapshotIn,
disallowList?: PartialDeep>,
options?: Partial>
) => readonly [React.FC, () => Instance];
`

#### Arguments

| param | type | required | description |
| ------------ | --------------------------------- | -------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| store | T extends IAnyModelType | yes | the mst model to instantiate |
| storage | StorageOptions | yes | the storage to use. Use defaultStorage from mst-persistent-store/dist//storage to use the @react-native-async-storage/async-storage (for React Native) or localforage (for Web) backed default storage. |
| init | SnapshotIn | yes | the init data of the store |
| disallowList | PartialDeep> | no | the part of the store that should not be persisted. See notes below |
| options | Partial | no | Various options to change store behavior |

#### PersistentStoreOptions

All Properties are optional.

| property | type | default | description |
| ---------- | ------------------------------ | ---------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| storageKey | string | persistentStore | the key to use as the localforage key. Must be
changed when using multiple stores in the same
app to avoid overriding data. |
| writeDelay | number | 1500 | On Repeated Store Update, it's advisable to wait
a certain time before updating the persistent
storage with new snapshot. This value controls the
debounce delay. |
| logging | boolean | true is dev
false in prod | Whether to enable logging. |
| devtool | boolean | true in dev
false in prod | Whether to integrate with mobx-devtool |
| onHydrate | (store: Instance) => void | none | Callback to run after hydration is done. |

Notes

$3

disallowList` is used to specify the part of the store that should not be persisted. This is useful when you have some part of the store that should not be persisted. For example, you may have a part of the store that is used for UI state management and should not be persisted.

This is a deep partial of the store snapshot. Anything passed here will replace the value on hydration.

License

This package is licensed under the MIT License.

Contribution

Any kind of contribution is welcome. Thanks!