blocks|key|3987394|text|我认为让一个服务负责在localStorage中存储数据是明智的。因此，您可能希望创建一个具有get和set函数的服务。您可以在redux中从effect调用服务。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3987395|在我看来，减速器是用来改变状态的。|3987396|您还可以使用rxjs等待reducer更新您的状态，然后获取它并使用您的服务将其保存到localStorage。|3987397|顺便说一句，依赖于你的需求，我真的看不出你为什么不应该在localStorage中存储数据，只要你记住你的redux状态是你唯一的事实。在我看来，将数据存储在某个地方以在初始化时恢复该状态是一个很好的方法。|3987398|下面是一个使用ngrx的示例：|3987399|@Effect()
myAction$:+Observable<Action>+=+this.actions$.pipe(
++ofType<MyAction>(actions.myAction),
++debounceTime(300),
++switchMap((action)+=>
++++this.service.post(action.dto).pipe(
++++++map((response:+SomeDto)+=>+{
++++++++//+This+updates+the+state+using+a+reducer
++++++++return+new+CreateShortenedLinkSuccess(response);
++++++}),
++++++tap((value)+=>+{
++++++++//+Here,+you+can+use+the+value+param,+to+save
++++++++//+changes+to+localStorage
++++++++this.router.navigate([`/mgmt/link/${value.dto.id}`]);
++++++}),
++++++catchError((response:+HttpErrorResponse)+=>+{
++++++++//+Do+scary+stuff
++++++})
++++)
++)
);|code-block|syntax|javascript|3987400|entityMap^0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|R|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|S|8|@]|9|@]|A|$]]|$1|F|3|G|5|6|7|T|8|@]|9|@]|A|$]]|$1|H|3|I|5|6|7|U|8|@]|9|@]|A|$]]|$1|J|3|K|5|L|7|V|8|@]|9|@]|A|$M|N]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

I think it's wise to make a service responsible for storing your data from and to localStorage. So you may want to create a service with a get and a set function. You can call the service from an effect in redux. 

In my opinion, the reducer is there to change the state.

You can also use rxjs to wait for the reducer to update your state, and then grab that and save it to localStorage using your service.

By the way, depening on you needs I don't really see any reason why you should not store data in localStorage as long as (when using redux) you keep in mind that you redux state is your single and only truth. Storing data somewhere to restore that state on initialization is a good approach in my hounest opinion.

Here is an example using ngrx :

<pre><code>@Effect()
myAction$: Observable&lt;Action&gt; = this.actions$.pipe(
 ofType&lt;MyAction&gt;(actions.myAction),
 debounceTime(300),
 switchMap((action) =&gt;
 this.service.post(action.dto).pipe(
 map((response: SomeDto) =&gt; {
 // This updates the state using a reducer
 return new CreateShortenedLinkSuccess(response);
 }),
 tap((value) =&gt; {
 // Here, you can use the value param, to save
 // changes to localStorage
 this.router.navigate([`/mgmt/link/${value.dto.id}`]);
 }),
 catchError((response: HttpErrorResponse) =&gt; {
 // Do scary stuff
 })
 )
 )
);
</code></pre>

blocks|key|3983466|text|我发现@Zaid+Crouch是一个很棒的工具，但它不能处理来自不同窗口(tab/iframe/popup)的本地存储更新。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3983467|import+{+useReducer,+useEffect,+Dispatch+}+from+'react'

//+Credits:+https://stackoverflow.com/questions/54346866/save-to-localstorage-from-reducer-hook
export+type+ReducerType<T>+=+(state:+T,+action:+ActionType)+=>+(T)
export+type+InitType<T>+=+(state:+T)+=>+void
export+interface+ActionType+{
++++type:+string
}

var+dispatcher:Dispatch<ActionType>+%7C+null+=+null

const+LOCAL_STORAGE_UPDATED_IN_A_DIFFERENT_WINDOW+=+"LOCAL_STORAGE_UPDATED_IN_A_DIFFERENT_WINDOW"
export+function+useLocallyPersistedReducer<T>
++++(reducer:+ReducerType<T>,+defaultState:+T,+storageKey:+string,+init?:InitType<T>)+:+[T,+Dispatch<ActionType>]+{

++++const+reducerWrapper+=+(status:+T,+action:+ActionType)+=>+{
++++++++switch+(action.type){
++++++++++++case+LOCAL_STORAGE_UPDATED_IN_A_DIFFERENT_WINDOW:
++++++++++++++++const+statusReadFromLocalStorage+=+JSON.parse(localStorage.getItem(storageKey)+%7C%7C+"{}")
++++++++++++++++return+statusReadFromLocalStorage
++++++++++++default:+return+reducer(status,+action)
++++++++}
++++}

++++const+[state,+dispatch]+=+useReducer(reducerWrapper,+defaultState,+(defaultState)+=>+{
++++++++const+persisted+=+JSON.parse(localStorage.getItem(storageKey)+as+string)
++++++++return+persisted+!==+null
++++++++++++?+persisted
++++++++++++:+init+?+init(defaultState)+:+defaultState
++++})

++++//+NOTE+Even+if+this+codes+runs+multiple+time+we+add+only+one+event+listener+as+long+as+the+callback+is+singleton
++++dispatcher+=+dispatch
++++window.addEventListener('storage',+listenForStorageChangesInOtherWindows,+{once:+true});

++++useEffect(()+=>+{
++++++++localStorage.setItem(storageKey,+JSON.stringify(state))
++++++++//+eslint-disable-next-line+react-hooks/exhaustive-deps
++++},+[localStorage,+storageKey,+state])

++++return+[state,+dispatch]
}

const+listenForStorageChangesInOtherWindows+=+(key:+any)+=>+{
++++dispatcher+&&+dispatcher({type:+LOCAL_STORAGE_UPDATED_IN_A_DIFFERENT_WINDOW})
}|code-block|syntax|javascript|3983468|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

I found the @Zaid Crouch a great one but it doesn't handle local storage updates coming from different windows (tabs/iframe/popup).

<pre><code>import { useReducer, useEffect, Dispatch } from 'react'

// Credits: https://stackoverflow.com/questions/54346866/save-to-localstorage-from-reducer-hook
export type ReducerType&lt;T&gt; = (state: T, action: ActionType) =&gt; (T)
export type InitType&lt;T&gt; = (state: T) =&gt; void
export interface ActionType {
 type: string
}

var dispatcher:Dispatch&lt;ActionType&gt; | null = null

const LOCAL_STORAGE_UPDATED_IN_A_DIFFERENT_WINDOW = "LOCAL_STORAGE_UPDATED_IN_A_DIFFERENT_WINDOW"
export function useLocallyPersistedReducer&lt;T&gt;
 (reducer: ReducerType&lt;T&gt;, defaultState: T, storageKey: string, init?:InitType&lt;T&gt;) : [T, Dispatch&lt;ActionType&gt;] {

 const reducerWrapper = (status: T, action: ActionType) =&gt; {
 switch (action.type){
 case LOCAL_STORAGE_UPDATED_IN_A_DIFFERENT_WINDOW:
 const statusReadFromLocalStorage = JSON.parse(localStorage.getItem(storageKey) || "{}")
 return statusReadFromLocalStorage
 default: return reducer(status, action)
 }
 }

 const [state, dispatch] = useReducer(reducerWrapper, defaultState, (defaultState) =&gt; {
 const persisted = JSON.parse(localStorage.getItem(storageKey) as string)
 return persisted !== null
 ? persisted
 : init ? init(defaultState) : defaultState
 })

 // NOTE Even if this codes runs multiple time we add only one event listener as long as the callback is singleton
 dispatcher = dispatch
 window.addEventListener('storage', listenForStorageChangesInOtherWindows, {once: true});

 useEffect(() =&gt; {
 localStorage.setItem(storageKey, JSON.stringify(state))
 // eslint-disable-next-line react-hooks/exhaustive-deps
 }, [localStorage, storageKey, state])

 return [state, dispatch]
}

const listenForStorageChangesInOtherWindows = (key: any) =&gt; {
 dispatcher &amp;&amp; dispatcher({type: LOCAL_STORAGE_UPDATED_IN_A_DIFFERENT_WINDOW})
}
</code></pre>

I'm using the useReducer hook to save some global state. Because I would like to save some settings when the browser is closed, I save those settings to local storage. 

At the moment I use dispatch to save the setting and a separate function to save this to local storage, but it would be nice if the setting is automatically saved after dispatch. (sometimes I forget to save to local storage and have a difference between state/local storage)

Reading the state from local storage is not a problem. I use the initialState parameter in the useReducer hook for this.

I think the answer is to not do it, but what is the alternative? (without using redux)

Save to localStorage from reducer hook

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我正在使用useReducer钩子来保存一些全局状态。因为我想在浏览器关闭时保存一些设置，所以我将这些设置保存到本地存储中。目前，我使用分派保存设置，并使用一个单独的函数将其保存到本地存储，但如果设置在分派后自动保存就更好了。(有时我忘记保存到本地存储，并且状态/本地存储之间存在差异)从本地存储中读取状态不是问题。为此...

问从减速机挂钩保存到localStorage
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