[angular] Angular + Material - How to refresh a data source (mat-table)

I did some more research and found this place to give me what I needed - feels clean and relates to update data when refreshed from server: https://blog.angular-university.io/angular-material-data-table/

Most credits to the page above. Below is a sample of how a mat-selector can be used to update a mat-table bound to a datasource on change of selection. I am using Angular 7. Sorry for being extensive, trying to be complete but concise - I have ripped out as many non-needed parts as possible. With this hoping to help someone else getting forward faster!

organization.model.ts:

export class Organization {
    id: number;
    name: String;
}

organization.service.ts:

import { Observable, empty } from 'rxjs';
import { of } from 'rxjs';

import { Organization } from './organization.model';

export class OrganizationService {
  getConstantOrganizations(filter: String): Observable<Organization[]> {
    if (filter === "All") {
      let Organizations: Organization[] = [
        { id: 1234, name: 'Some data' }
      ];
      return of(Organizations);
     } else {
       let Organizations: Organization[] = [
         { id: 5678, name: 'Some other data' }
       ];
     return of(Organizations);
  }

  // ...just a sample, other filterings would go here - and of course data instead fetched from server.
}

organizationdatasource.model.ts:

import { CollectionViewer, DataSource } from '@angular/cdk/collections';
import { Observable, BehaviorSubject, of } from 'rxjs';
import { catchError, finalize } from "rxjs/operators";

import { OrganizationService } from './organization.service';
import { Organization } from './organization.model';

export class OrganizationDataSource extends DataSource<Organization> {
  private organizationsSubject = new BehaviorSubject<Organization[]>([]);

  private loadingSubject = new BehaviorSubject<boolean>(false);

  public loading$ = this.loadingSubject.asObservable();

  constructor(private organizationService: OrganizationService, ) {
    super();
  }

  loadOrganizations(filter: String) {
    this.loadingSubject.next(true);

    return this.organizationService.getOrganizations(filter).pipe(
      catchError(() => of([])),
      finalize(() => this.loadingSubject.next(false))
    ).subscribe(organization => this.organizationsSubject.next(organization));
  }

  connect(collectionViewer: CollectionViewer): Observable<Organization[]> {
    return this.organizationsSubject.asObservable();
  }

  disconnect(collectionViewer: CollectionViewer): void {
    this.organizationsSubject.complete();
    this.loadingSubject.complete();
  }
}

organizations.component.html:

<div class="spinner-container" *ngIf="organizationDataSource.loading$ | async">
    <mat-spinner></mat-spinner>
</div>

<div>
  <form [formGroup]="formGroup">
    <mat-form-field fxAuto>
      <div fxLayout="row">
        <mat-select formControlName="organizationSelectionControl" (selectionChange)="updateOrganizationSelection()">
          <mat-option *ngFor="let organizationSelectionAlternative of organizationSelectionAlternatives"
            [value]="organizationSelectionAlternative">
            {{organizationSelectionAlternative.name}}
          </mat-option>
        </mat-select>
      </div>
    </mat-form-field>
  </form>
</div>

<mat-table fxLayout="column" [dataSource]="organizationDataSource">
  <ng-container matColumnDef="name">
    <mat-header-cell *matHeaderCellDef>Name</mat-header-cell>
    <mat-cell *matCellDef="let organization">{{organization.name}}</mat-cell>
  </ng-container>

  <ng-container matColumnDef="number">
    <mat-header-cell *matHeaderCellDef>Number</mat-header-cell>
    <mat-cell *matCellDef="let organization">{{organization.number}}</mat-cell>
  </ng-container>

  <mat-header-row *matHeaderRowDef="displayedColumns"></mat-header-row>
  <mat-row *matRowDef="let row; columns: displayedColumns"></mat-row>
</mat-table>

organizations.component.scss:

.spinner-container {
    height: 360px;
    width: 390px;
    position: fixed;
}

organization.component.ts:

import { Component, OnInit } from '@angular/core';
import { FormGroup, FormBuilder } from '@angular/forms';
import { Observable } from 'rxjs';

import { OrganizationService } from './organization.service';
import { Organization } from './organization.model';
import { OrganizationDataSource } from './organizationdatasource.model';

@Component({
  selector: 'organizations',
  templateUrl: './organizations.component.html',
  styleUrls: ['./organizations.component.scss']
})
export class OrganizationsComponent implements OnInit {
  public displayedColumns: string[];
  public organizationDataSource: OrganizationDataSource;
  public formGroup: FormGroup;

  public organizationSelectionAlternatives = [{
    id: 1,
    name: 'All'
  }, {
    id: 2,
    name: 'With organization update requests'
  }, {
    id: 3,
    name: 'With contact update requests'
  }, {
    id: 4,
    name: 'With order requests'
  }]

  constructor(
    private formBuilder: FormBuilder,
    private organizationService: OrganizationService) { }

  ngOnInit() {
    this.formGroup = this.formBuilder.group({
      'organizationSelectionControl': []
    })

    const toSelect = this.organizationSelectionAlternatives.find(c => c.id == 1);
    this.formGroup.get('organizationSelectionControl').setValue(toSelect);

    this.organizationDataSource = new OrganizationDataSource(this.organizationService);
    this.displayedColumns = ['name', 'number' ];
    this.updateOrganizationSelection();
  }

  updateOrganizationSelection() {
    this.organizationDataSource.loadOrganizations(this.formGroup.get('organizationSelectionControl').value.name);
  }
}