如何使用@ ngrx/store获取State对象的当前值? [英] How to get current value of State object with @ngrx/store?

问题描述

我的服务类在调用Web服务之前需要从我的状态获取一个名为dataForUpdate的属性.目前，我正在这样做:

 constructor(public _store: Store < AppState > ,
  public _APIService: APIService) {

  const store$ = this._store.select('StateReducer');

  .../...

  let update = this.actions$.filter(action => action.type == UPDATE)
    .do((action) => this._store.dispatch({
      type: REDUCER_UPDATING,
      payload: action.payload
    })) **
    * GET STATE ** *= => .mergeMap(action => store$.map((state: AppState) => state.dataForUpdate).distinctUntilChanged(),
      (action, dataForUpdate) {
        return {
          type: action.type,
          payload: {
            employee: action.payload,
            dataForUpdate: dataForUpdate
          }
        };
      }) *
    AND CALL API *= => .mergeMap(action => this._APIService.updateEmployee(action.payload.employee, action.payload.dataForUpdate),
      (action, APIResult) => {
        return {
          type: REDUCER_UPDATED
        }
      })
    .share();


  .../...

  let all = Observable.merge(update, ....);
  all.subscribe((action: Action) => this._store.dispatch(action));

}
 

我正在使用angular2-store-example( https://github.com/ngrx/angular2-store-example/blob/master/src/app/users/models/users.ts )作为指南.). >

我想知道是否存在更好(更清洁)的方式?

实时示例: https://plnkr.co/edit/WRPfMzPolQsYNGzBUS1g?p=preview

解决方案

@ ngrx/store v1.x的原始答案

@ngrx/store扩展了 BehaviorSubject ，并且具有您可以使用的value属性.

this._store.value

这将是您应用的当前状态，然后您可以在其中选择属性，过滤器，地图等...

更新:

花点时间看一下示例中的内容(:要获得dataForUpdate的当前值，可以使用:

let x = this._store.value.StateReducer.dataForUpdate;
console.log(x); // => { key: "123" }

@ ngrx/store v2.x的更新

随着版本2的更新，如文档中所述，删除了value :

已删除用于同步将最新状态值从存储中拉出的API.相反，如果必须获取状态值，则始终可以依赖subscribe()同步运行:

function getState(store: Store<State>): State {
    let state: State;

    store.take(1).subscribe(s => state = s);

    return state;
}

My service class, before calling a web service, needs to get a property called dataForUpdate from my state. Currently, I'm doing it like this:

constructor(public _store: Store < AppState > ,
  public _APIService: APIService) {

  const store$ = this._store.select('StateReducer');

  .../...

  let update = this.actions$.filter(action => action.type == UPDATE)
    .do((action) => this._store.dispatch({
      type: REDUCER_UPDATING,
      payload: action.payload
    })) **
    * GET STATE ** *= => .mergeMap(action => store$.map((state: AppState) => state.dataForUpdate).distinctUntilChanged(),
      (action, dataForUpdate) {
        return {
          type: action.type,
          payload: {
            employee: action.payload,
            dataForUpdate: dataForUpdate
          }
        };
      }) *
    AND CALL API *= => .mergeMap(action => this._APIService.updateEmployee(action.payload.employee, action.payload.dataForUpdate),
      (action, APIResult) => {
        return {
          type: REDUCER_UPDATED
        }
      })
    .share();


  .../...

  let all = Observable.merge(update, ....);
  all.subscribe((action: Action) => this._store.dispatch(action));

}

I'm using angular2-store-example (https://github.com/ngrx/angular2-store-example/blob/master/src/app/users/models/users.ts) as a guide to follow.

I'm wondering if a better (cleaner) way exists?

Live example: https://plnkr.co/edit/WRPfMzPolQsYNGzBUS1g?p=preview

解决方案

Original answer for @ngrx/store v1.x

@ngrx/store extends BehaviorSubject and it has a value property you can use.

this._store.value

that will be the current state of your app, and from there you can select properties, filter, map etc...

update:

Took me a while to figure what's what in your example (: To get current value of dataForUpdate, you can use:

let x = this._store.value.StateReducer.dataForUpdate;
console.log(x); // => { key: "123" }

Update for @ngrx/store v2.x

With the update to version 2, value was removed as described in docs:

The APIs for synchronously pulling the most recent state value out of Store have been removed. Instead, you can always rely on subscribe() running synchronously if you have to get the state value:

function getState(store: Store<State>): State {
    let state: State;

    store.take(1).subscribe(s => state = s);

    return state;
}

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