We have Product instances that we are adding to a shopping cart that is backed by a Firefly Semantics Slice Entity Store (EStore). As the Widget we want a snapshot of the number of instances in the cart.

Here is a YouTube demo.

Approach

The Firefly Semantics Entity Store has a countSnapshot():number method that we can call to get the count of the number of entities in the store.

interface Product {
id: string;
name: string;
}
const P1: Product = {
    id: '1',
    name: 'Soap',
};
const P2: Product = {
    id: '1',
    name: 'Soap',
};
const cart: EStore<Product> = new EStore<Product>();
cart.post(P1);
cart.post(P2);
const count = cart.countSnapshot();
console.log(count);
// Logs 2 

Demo