Wei-En's Pager Code Submission

server.js

const routes = [
    {
        method: 'GET',
        path: '/locations',
        handler: async (request, h) => {

            const db = server.app.db;
            const locationCollection = db.collection('locations');

            // query all locations
            const documents = await locationCollection.find({}).toArray();
            return documents;
        }
    }, 
    {
        method: 'GET',
        path: '/locations/{id}/items',
        handler: async (request, h) => {
            const locationId = request.params.id

            const db = server.app.db;

            const locationsCollection = db.collection('locations');
            const locations = 
                await locationsCollection
                    .find(
                        {
                            locationId: Number(locationId)
                        }
                    )
                    .toArray();
            
            if (locations.length === 0) {
                return h.response().code(404);
            } 

            const itemsCollection = db.collection('items');


            // find single location
            const items = 
                await itemsCollection
                    .find(
                        {
                            locationId: Number(locationId)
                        }
                    )
                    .toArray();
            return items;
        }
    },
    {
        method: 'POST',
        path: '/locations/{id}/order',
        handler: async (request, h) => {
            const locationId = request.params.id

            const db = server.app.db;

            const locationsCollection = db.collection('locations');
            const locations = 
                await locationsCollection
                    .find(
                        {
                            locationId: Number(locationId)
                        }
                    )
                    .toArray();
            
            if (locations.length === 0) {
                return h.response().code(404);
            }
            
            // calculate the total
            let total = 0;

            for (const i of request.payload.items) {
                const item = 
                    await db.collection('items')
                    .findOne(
                        {
                            itemId: i.itemId
                        }
                    );
                total = total + (i.quantity * item.price);
            }


            const ordersCollection = db.collection('orders');

            const order = 
                await ordersCollection
                    .insertOne(request.payload);
            
            const returnedOrder = order.ops[0];
            returnedOrder.total = total;

            return h.response(order.ops[0]).code(201);

        }
    }
];