如何通过@ngrx/store获取State对象的当前值？

import { createReducer, on } from '@ngrx/store';
import { increment, decrement } from './counter.actions';

export const initialState = { count: 0 };

const _counterReducer = createReducer(
  initialState,
  on(increment, state => ({ count: state.count + 1 })),
  on(decrement, state => ({ count: state.count - 1 }))
);

export function counterReducer(state, action) {
  return _counterReducer(state, action);
}

import { NgModule } from '@angular/core';
import { StoreModule } from '@ngrx/store';
import { counterReducer } from './counter.reducer';

@NgModule({
  imports: [
    StoreModule.forRoot({ counter: counterReducer })
  ]
})
export class AppModule { }

import { Component } from '@angular/core';
import { Store } from '@ngrx/store';
import { selectCounterState } from './counter.selectors';

@Component({
  selector: 'app-counter',
  template: `
    <div>Count: {{ count$ | async }}</div>
    <button (click)="increment()">Increment</button>
    <button (click)="decrement()">Decrement</button>
  `
})
export class CounterComponent {
  count$ = this.store.select(selectCounterState);

  constructor(private store: Store) {}

  increment() {
    this.store.dispatch(increment());
  }

  decrement() {
    this.store.dispatch(decrement());
  }
}

import { createSelector } from '@ngrx/store';
import { AppState } from './app.state';

export const selectCounterState = (state: AppState) => state.counter;