data-source-generic-class.ts

import { Observable } from 'rxjs/Observable';
import { DataSource } from '@angular/cdk/collections';
import { BehaviorSubject } from 'rxjs/BehaviorSubject';

export class EntityDataSource<T extends { id: string }> extends DataSource<T> {
  private source: BehaviorSubject<T[]> = new BehaviorSubject<T[]>([]);

  get data(): T[] {
    return this.source.value;
  }

  addOne(item: T): void {
    this.source.next([...this.data, item]);
  }

  addMany(items: T[]): void {
    this.source.next([...this.data, ...items]);
  }

  remove(...ids: string[]): void {
    const duplicatedData = [...this.data];
    this.source.next(duplicatedData.filter(item => !ids.includes(item.id)));
  }

  connect(): Observable<T[]> {
    return this.source.asObservable();
  }

  disconnect() {
    this.source.complete();
  }
}