redux persisting the state to the local storage

loadState()&saveState()

loadState()：按照对应的key: state，从localStorage中取出对应的字符串，将字符串解析成对应的JSON
saveState()：接受一个state，将其序列化为字符串，存入localStorage中

<!--localStorage.js-->
export const loadState = () => {
	try {
		const serializedState = localStorage.getItem('state');
		if(serializedState === null) {
			return undefined;
		}
		return JSON.parse(serializedState);
	} catch (err) {
		return undefined;
	}
}
export const saveState = (state) => {
	try {
		const serializedState = JSON.stringify(state);
		localStorage.setItem('state', serializedState);
	} catch (err) {
		// Ignore write errors
	}
}

Using localStorage.js

// 取
const store = createStore(todoApp, loadState())
 
// 存
store.subscribe(() => {
	saveState({
 		todos: store.getState().todos
	})
})

Throttling saveState()

每一秒更新一次localStorage

import throttle from 'lodash/throttle'

store.subscribe(throttle(() => {
	saveState({
		todos: store.getState().todos
	})
}, 1000))