# natur-persist-async

# introduction

asynchronous persistent cache middleware for natur state manager
synchronization operation has a certain delay, use anti-shake for synchronization operation

# demo

import { createStore } from 'natur';
import createPersistMiddleware from 'natur-persist-async';
import AsyncStorage from '@react-native-community/async-storage';


const { middleware, getData, clearData } = createPersistMiddleware({
  name: '_data',
  time: 500,
  exclude: ['module1', /^module2$/],
  include: ['module3', /^module4$/],
  specific: {
    user: 0,
  },
  setItem: async (key: string, value: any) => {
    try {
      await AsyncStorage.setItem(key, JSON.stringify(value));
    } catch (e) {
      // saving error
    }
  },
  getItem: async (key: string) => {
    try {
      const value = await AsyncStorage.getItem(key);
      return !!value ? JSON.parse(value) : value;
    } catch (e) {
      // get error
    }
  },
  removeItem: async (key: string) => {
    try {
      await AsyncStorage.removeItem(key);
    } catch (e) {
      // remove error
    }
  },
});

// clearData(); clear cached data


const store = createStore(
  {},
  {}
  {
    middlewares: [
      middleware, // use middleware to synchronize data to storage
    ]
  }
);

// the store fills the cached data
getData().then(data => store.globalSetStates(data));

# parameter

# createPersistMiddleware options

# name

require: false
type:string
default:'_data'
when adding elements to localStorage, this name will be added as a prefix when setting the name of the key to prevent naming conflicts between different applications

# time

require: false
type:number
default:100
synchronization delay. When synchronizing data to localStorage, use debounce as a synchronization mechanism, and there is a certain delay.

# exclude

require: false
type:Array<string|RegExp>
when synchronizing module data to localStorage, you can configure whether to ignore caching certain modules

# include

require:false
type:Array<string|RegExp>
when synchronizing module data to localStorage, you can configure whether to cache only certain modules, exclude priority is higher than include

# specific

require:false
type:{[moduleName: string]: number}
configure the delay time of some modules, if the number is 0, then it will be a synchronous buffer without anti-shake mechanism

# setItem

require:true
type:(key: string, value: any) => Promise<any>
implementation of saving data to cache

# getItem

require:true
type:(key: string) => Promise<any>
get cached data implementation

# removeItem

require:true
type:(key: string) => Promise<any>
delete cache data implementation

# createPersistMiddleware return value

# middleware

middleware, used to intercept store data and trigger the caching mechanism

# getData

get the data in the cache

# clearData

clear data in cache