ui/angular/src/app/loader/loader.component.ts

import {Component, OnInit, OnDestroy} from "@angular/core";
import {Subscription} from "rxjs/Subscription";
import {LoaderService} from "./loader.service";
import {LoadingState} from "./loader.state";

@Component({
  selector: "app-loader",
  templateUrl: "./loader.component.html",
  styleUrls: ["./loader.component.css"]
})
export class LoaderComponent implements OnInit {
  show = false;
  private subscription: Subscription;

  constructor(
    private loaderService: LoaderService
  ) {
  }

  ngOnInit() {
    this.subscription = this.loaderService.LoadingState
      .subscribe((state: LoadingState) => {
        this.show = state.show;
      });
  }

  ngOnDestroy() {
    this.subscription.unsubscribe();
  }
}