in codelab-initial-state/public/js/homepage.js [154:170]
setCartItems(items) {
let itemIds;
if (items) {
this.cartItems = items.docs.map(doc => doc.data());
itemIds = items.docs.map(doc => doc.id);
} else {
this.cartItems = [];
itemIds = [];
}
// For any item in the cart, we disable the add button
this.itemCardList.getAll().forEach(itemCard => {
const inCart = itemIds.indexOf(itemCard.id) >= 0;
itemCard.setAddEnabled(!inCart);
});
}