astro/examples/ssr/src/api.ts

export interface Product {
	id: number;
	name: string;
	price: number;
	image: string;
}

interface User {
	id: number;
}

interface Cart {
	items: Array<{
		id: number;
		name: string;
		count: number;
	}>;
}

async function get<T>(
	incomingReq: Request,
	endpoint: string,
	cb: (response: Response) => Promise<T>
): Promise<T> {
	const origin = new URL(incomingReq.url).origin;
	const response = await fetch(`${origin}${endpoint}`, {
		credentials: 'same-origin',
		headers: incomingReq.headers,
	});
	if (!response.ok) {
		// TODO make this better...
		throw new Error('Fetch failed');
	}
	return cb(response);
}

export async function getProducts(incomingReq: Request): Promise<Product[]> {
	return get<Product[]>(incomingReq, '/api/products', async (response) => {
		const products: Product[] = await response.json();
		return products;
	});
}

export async function getProduct(incomingReq: Request, id: number): Promise<Product> {
	return get<Product>(incomingReq, `/api/products/${id}`, async (response) => {
		const product: Product = await response.json();
		return product;
	});
}

export async function getUser(incomingReq: Request): Promise<User> {
	return get<User>(incomingReq, `/api/user`, async (response) => {
		const user: User = await response.json();
		return user;
	});
}

export async function getCart(incomingReq: Request): Promise<Cart> {
	return get<Cart>(incomingReq, `/api/cart`, async (response) => {
		const cart: Cart = await response.json();
		return cart;
	});
}

export async function addToUserCart(id: number | string, name: string): Promise<void> {
	await fetch(`${location.origin}/api/cart`, {
		credentials: 'same-origin',
		method: 'POST',
		mode: 'no-cors',
		headers: {
			'Content-Type': 'application/json',
			Cache: 'no-cache',
		},
		body: JSON.stringify({
			id,
			name,
		}),
	});
}