How to create an Observable from static data similar to http one in Angular?

Question

I am having a service that has this method:

export class TestModelService {

    public testModel: TestModel;

    constructor( @Inject(Http) public http: Ht         


        

Answer 1

This way you can create Observable from data, in my case I need to maintain shopping cart:

service.ts

export class OrderService {
    cartItems: BehaviorSubject> = new BehaviorSubject([]);
    cartItems$ = this.cartItems.asObservable();

    // I need to maintain cart, so add items in cart

    addCartData(data) {
        const currentValue = this.cartItems.value; // get current items in cart
        const updatedValue = [...currentValue, data]; // push new item in cart

        if(updatedValue.length) {
          this.cartItems.next(updatedValue); // notify to all subscribers
        }
      }
}

Component.ts

export class CartViewComponent implements OnInit {
    cartProductList: any = [];
    constructor(
        private order: OrderService
    ) { }

    ngOnInit() {
        this.order.cartItems$.subscribe(items => {
            this.cartProductList = items;
        });
    }
}