I was searching for a concrete example on when and how to use RxJs BehaviorSubect. So I found an example in a Shopping cart web application. The BehaviorSubject is used in a shopping cart service. Here is an example of its implementation.
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export class GlobalService {
cart$: BehaviorSubject<Cart> = new BehaviorSubject(new Cart);
lineItems$: BehaviorSubject<LineItem[]> = new BehaviorSubject([]);
constructor() {
let cart = new Cart;
this.cart$.next(cart);
}
get cart() {
return this.cart$.getValue();
}
set cart(cart) {
this.cart$.next(cart);
}
set lineItems(lineItems) {
this.lineItems$.next(lineItems);
}
get lineItems() {
return this.lineItems$.getValue();
}
addItemToCart(variant: Variant) {
let quant = prompt("You want to add " + variant.title + " to the cart. Please, enter quantity", '1')
this.lineItems.push(
{
id: '',
title: variant.title,
quantity: +quant,
variant: variant,
}
);
this.lineItems = this.lineItems;
}
removeItemFromCart(i) {
this.lineItems.splice(i, 1);
}
}