e-book

products-loaded.guard.ts

import { Injectable } from '@angular/core';
import { CanActivate } from '@angular/router';
import { Store, select } from '@ngrx/store';
import { Observable, of } from 'rxjs';
import { take, tap, filter, switchMap, catchError } from 'rxjs/operators';
import { MarketPlaceAnchorModule } from '../market-place-anchor.module';
import * as fromStore from '../store/reducers';
import { PurchaseContractActions } from '../store/actions';

@Injectable({
  providedIn: MarketPlaceAnchorModule
 })
export class ProductsLoadedGuard implements CanActivate {
  constructor(private store: Store<fromStore.AppState>) {}

  canActivate(): Observable<boolean> {
    return this.waitForProductsToLoad().pipe(
        switchMap(() => of(true)),
        catchError(() => of(false))
    );
  }

  waitForProductsToLoad(): Observable<boolean> {
      return this.store.pipe(
        select(fromStore.isProductsLoaded),
         tap(loaded => {
          if (!loaded) {
            this.store.dispatch(PurchaseContractActions.loadProducts());
          }
        }),
        filter(loaded => loaded),
        take(1)
      );
  }
}