import { of, Observable } from 'rxjs';
import { PreloadingStrategy, Route } from '@angular/router';

import { Injectable } from '@angular/core';

@Injectable({
  providedIn: 'root'
})
export class NaSelectivePreloadStrategy implements PreloadingStrategy {
  preloadedModules: string[] = [];

  preload(route: Route, load: Function): Observable<any> {
    if (route.data && route.data['preload']) {
      // add the route path to our preloaded module array
      this.preloadedModules.push(route.path);

      // log the route path to the console
      // console.log('Preloaded: ' + route.path);

      return load();
    } else {
      return of(null);
    }
  }
}