Improve Carts reliability

Nicer empty cart page
Check on page load if cart is valid

front/src/lib/cart.ts

@@ -1,13 +1,21 @@
 import { get, writable } from "svelte/store";
 
-import type { CartItem } from './types';
-import { getItemByUUID } from "./test-api";
+import type { Item, CartItem } from './types';
+import { getItemByUUID, postVerifyCart } from "./test-api";
 
 
 // Load content from localstorage
-let local = [];
+let local: CartItem[] = [];
 try {
-    local = JSON.parse(localStorage.getItem("basket")) || []
+    let verified = await postVerifyCart(
+        JSON.parse(localStorage.getItem("basket")) || []
+    );
+
+    if (verified instanceof Error) {
+        throw new Error("Bruh");
+    }
+
+    local = <CartItem[]>verified;
 } catch {
     console.error("Failed to load cart")
 }
@@ -27,12 +35,22 @@ function createCartStore() {
         });
 
         if (!found) {
-            const newItem: CartItem = {
-                uuid: uuid,
-                amount: amount,
-                data: await getItemByUUID(uuid),
-            };
-            cart.update((cart: CartItem[]) => [...cart, newItem]);
+            let cartData: Item;
+
+            try {
+                let data: Item | Error = await getItemByUUID(uuid);
+                if (data instanceof Error) {
+                    return;
+                }
+                cartData = <Item>data;
+            } finally {
+                const newItem: CartItem = {
+                    uuid: uuid,
+                    amount: amount,
+                    data: cartData,
+                };
+                cart.update((cart: CartItem[]) => [...cart, newItem]);
+            }
         }
 
         // Remove items that have an amount of 0 or lower

front/src/lib/test-api.ts

@@ -1,10 +1,10 @@
-import type { Item } from './types';
+import type {CartItem, Item} from './types';
 import TestData from './test-data';
 
 
 let cache = {
-    announcement_banner: null,
-    popular_today: null,
+    announcement_banner: undefined,
+    popular_today: undefined,
 };
 
 
@@ -15,28 +15,30 @@ async function fakeDelay(timeout: number = 1000) {
 }
 
 
-export async function getAnnouncements() {
+export async function getAnnouncements(): Promise<{image: string}> {
     if (cache.announcement_banner) {
         return cache.announcement_banner;
     }
-
     const data = {
         image: "/BannerExampleImage.jpg",
     };
     cache.announcement_banner = data;
+
     await fakeDelay(200)
+
     return data;
 }
 
 
-export async function getPopularToday() {
+export async function getPopularToday(): Promise<Item[]> {
     if (cache.popular_today) {
         return cache.popular_today;
     }
-
-    const data = TestData;
+    const data: Item[] = TestData;
     cache.popular_today = data;
+
     await fakeDelay(200)
+
     return data;
 }
 
@@ -61,8 +63,8 @@ export async function getMenuItems() {
 }
 
 
-export async function getItemsByUUID(items: string[]) {
-    let data = [];
+export async function getItemsByUUID(items: string[]): Promise<Item[] | Error> {
+    let data: Item[] = [];
 
     TestData.forEach((itemInDatabase: Item) => {
         items.forEach((itemInRequest) => {
@@ -82,9 +84,12 @@ export async function getItemsByUUID(items: string[]) {
 }
 
 
-export async function getItemByUUID(uuid: string) {
-    let data = await getItemsByUUID([uuid]);
+export async function getItemByUUID(uuid: string): Promise<Item | Error> {
+    let data: Item[] | Error = await getItemsByUUID([uuid]);
 
+    if (data instanceof Error) {
+        throw new Error("Resource could not be found");
+    }
     if (data.length != 1) {
         throw new Error("Resource could not be found");
     }
@@ -93,7 +98,7 @@ export async function getItemByUUID(uuid: string) {
 }
 
 
-export async function postContactEmail(name: string, email: string, message: string) {
+export async function postContactEmail(name: string, email: string, message: string): Promise<string | Error> {
     await fakeDelay(200)
 
     if (!name) {
@@ -110,3 +115,36 @@ export async function postContactEmail(name: string, email: string, message: str
 
     return "Check your email to confirm the message!";
 }
+
+export async function postVerifyCart(currentCartData: CartItem[]): Promise<CartItem[] | Error> {
+    if (currentCartData.length <= 0) {
+        return [];
+    }
+
+    let itemUUIDs: string[] = currentCartData.map((item) => item.uuid);
+    let verifiedItems: Item[] | Error = await getItemsByUUID(itemUUIDs);
+
+    if (verifiedItems instanceof Error) {
+        return new Error("Could not collect new cart information");
+    }
+
+    let newCartData: CartItem[] = [];
+    currentCartData.forEach((currentItem) => {
+        let data: Item;
+        verifiedItems.forEach((verifiedItem) => {
+            if (verifiedItem.uuid === currentItem.uuid) {
+                data = verifiedItem;
+            }
+        })
+
+        if (data) {
+            newCartData.push({
+                uuid: currentItem.uuid,
+                amount: currentItem.amount,
+                data: data,
+            });
+        }
+    });
+
+    return newCartData;
+}

front/src/lib/test-data.ts

@@ -49,7 +49,7 @@ const TestData: Item[] = [
         name: "GwaGwa",
         price: 69,
         labels: [Labels.nut],
-        // image: "/dab.jpg",
+        image: "/dab.jpg",
     },
     {
         uuid: "hogmelon",