From 24bcb816e510529ceb1015bfb53e19287cd1286d Mon Sep 17 00:00:00 2001
From: Delba de Oliveira <32464864+delbaoliveira@users.noreply.github.com>
Date: Tue, 19 Sep 2023 18:55:02 +0100
Subject: [PATCH] Add code for chapters 7-8 (#164)

* Rename file and add data fetches for overview page

* Rename calculations.ts to utils.ts

* Update code to match course

* Add temporary calculation

* Fix error

* Move types to data fetching file

* Add error handling

* Parallelize data fetches

* Add skeletons

* Add delayed data request

* Fix ts errors

* Code for chapter 8

* Fix error

* Clean up

---------

Co-authored-by: Stephanie Dietz <49788645+StephDietz@users.noreply.github.com>
---
 .../app/dashboard/invoices/[id]/edit/page.tsx |   2 +-
 dashboard/15-final/app/dashboard/loading.tsx  |   5 +
 dashboard/15-final/app/dashboard/page.tsx     |  37 ++++-
 dashboard/15-final/app/lib/data-fetches.ts    |  65 ---------
 dashboard/15-final/app/lib/data.ts            | 132 ++++++++++++++++++
 dashboard/15-final/app/lib/definitions.ts     |   8 ++
 .../app/lib/{calculations.ts => utils.ts}     |  52 +++++--
 dashboard/15-final/app/ui/customers/table.tsx |   4 +-
 .../app/ui/dashboard/latest-invoices.tsx      |  32 ++---
 .../15-final/app/ui/dashboard/overview.tsx    |  40 ------
 .../app/ui/dashboard/revenue-chart.tsx        |  13 +-
 dashboard/15-final/app/ui/invoices/table.tsx  |   2 +-
 dashboard/15-final/app/ui/skeletons.tsx       |  90 ++++++++++++
 dashboard/15-final/tailwind.config.ts         |   8 ++
 14 files changed, 338 insertions(+), 152 deletions(-)
 create mode 100644 dashboard/15-final/app/dashboard/loading.tsx
 delete mode 100644 dashboard/15-final/app/lib/data-fetches.ts
 create mode 100644 dashboard/15-final/app/lib/data.ts
 rename dashboard/15-final/app/lib/{calculations.ts => utils.ts} (53%)
 delete mode 100644 dashboard/15-final/app/ui/dashboard/overview.tsx
 create mode 100644 dashboard/15-final/app/ui/skeletons.tsx

diff --git a/dashboard/15-final/app/dashboard/invoices/[id]/edit/page.tsx b/dashboard/15-final/app/dashboard/invoices/[id]/edit/page.tsx
index 6aca81f..6f6931b 100644
--- a/dashboard/15-final/app/dashboard/invoices/[id]/edit/page.tsx
+++ b/dashboard/15-final/app/dashboard/invoices/[id]/edit/page.tsx
@@ -1,7 +1,7 @@
 import InvoiceForm from '@/app/ui/invoices/form';
 import { notFound } from 'next/navigation';
 import { Invoice } from '@/app/lib/definitions';
-import { fetchInvoiceById } from '@/app/lib/data-fetches';
+import { fetchInvoiceById } from '@/app/lib/data';
 
 export default async function Page({ params }: { params: { id: string } }) {
   const id = params.id ? parseInt(params.id) : null;
diff --git a/dashboard/15-final/app/dashboard/loading.tsx b/dashboard/15-final/app/dashboard/loading.tsx
new file mode 100644
index 0000000..3eeaa28
--- /dev/null
+++ b/dashboard/15-final/app/dashboard/loading.tsx
@@ -0,0 +1,5 @@
+import DashboardSkeleton from '@/app/ui/skeletons';
+
+export default function Loading() {
+  return <DashboardSkeleton />;
+}
diff --git a/dashboard/15-final/app/dashboard/page.tsx b/dashboard/15-final/app/dashboard/page.tsx
index 0a65819..80456ae 100644
--- a/dashboard/15-final/app/dashboard/page.tsx
+++ b/dashboard/15-final/app/dashboard/page.tsx
@@ -1,9 +1,40 @@
-import DashboardOverview from '@/app/ui/dashboard/overview';
+import Card from '@/app/ui/dashboard/card';
+import RevenueChart from '@/app/ui/dashboard/revenue-chart';
+import LatestInvoices from '@/app/ui/dashboard/latest-invoices';
+import {
+  fetchLatestInvoices,
+  fetchCounts,
+  fetchTotalAmountByStatus,
+} from '@/app/lib/data';
+import { Suspense } from 'react';
+import { RevenueChartSkeleton } from '@/app/ui/skeletons';
+
+export const dynamic = 'force-dynamic';
+
+export default async function Page() {
+  const latestInvoices = await fetchLatestInvoices();
+  const { numberOfInvoices, numberOfCustomers } = await fetchCounts();
+  const { totalPaidInvoices, totalPendingInvoices } =
+    await fetchTotalAmountByStatus();
 
-export default function Page() {
   return (
     <main>
-      <DashboardOverview />
+      <div className="grid gap-6 sm:grid-cols-2 lg:grid-cols-4">
+        <Card title="Collected" value={totalPaidInvoices} type="collected" />
+        <Card title="Pending" value={totalPendingInvoices} type="pending" />
+        <Card title="Total Invoices" value={numberOfInvoices} type="invoices" />
+        <Card
+          title="Total Customers"
+          value={numberOfCustomers}
+          type="customers"
+        />
+      </div>
+      <div className="mt-6 grid grid-cols-1 gap-6 md:grid-cols-4 lg:grid-cols-8">
+        <Suspense fallback={<RevenueChartSkeleton />}>
+          <RevenueChart />
+        </Suspense>
+        <LatestInvoices latestInvoices={latestInvoices} />
+      </div>
     </main>
   );
 }
diff --git a/dashboard/15-final/app/lib/data-fetches.ts b/dashboard/15-final/app/lib/data-fetches.ts
deleted file mode 100644
index 94f5f84..0000000
--- a/dashboard/15-final/app/lib/data-fetches.ts
+++ /dev/null
@@ -1,65 +0,0 @@
-import { sql } from '@vercel/postgres';
-
-export async function fetchAllInvoices() {
-  const invoicesData = await sql`SELECT * FROM invoices`;
-  return invoicesData.rows;
-}
-
-export async function fetchAllCustomers() {
-  const customersData = await sql`SELECT * FROM customers`;
-  return customersData.rows;
-}
-
-export async function fetchAllRevenue() {
-  const revenueData = await sql`SELECT * FROM revenue`;
-  return revenueData.rows;
-}
-
-export async function fetchFilteredInvoices(
-  searchTerm: string,
-  currentPage: number,
-  ITEMS_PER_PAGE: number,
-) {
-  const invoicesData = await sql`
-    SELECT 
-      invoices.*, 
-      customers.name AS customer_name, 
-      customers.email AS customer_email, 
-      customers.image_url AS customer_image
-    FROM 
-      invoices
-    JOIN 
-      customers ON invoices.customer_id = customers.id
-    WHERE 
-      invoices.id::text ILIKE ${`%${searchTerm}%`} OR
-      customers.name ILIKE ${`%${searchTerm}%`} OR
-      customers.email ILIKE ${`%${searchTerm}%`} OR
-      invoices.amount::text ILIKE ${`%${searchTerm}%`} OR
-      invoices.date::text ILIKE ${`%${searchTerm}%`} OR
-      invoices.status ILIKE ${`%${searchTerm}%`}
-    LIMIT ${ITEMS_PER_PAGE}
-    OFFSET ${(currentPage - 1) * ITEMS_PER_PAGE}
-  `;
-  return invoicesData.rows;
-}
-
-export async function fetchInvoiceCountBySearchTerm(searchTerm: string) {
-  const { rows: countRows } = await sql`
-  SELECT COUNT(*) 
-  FROM invoices 
-  LEFT JOIN customers ON invoices.customer_id = customers.id 
-  WHERE (invoices.id::text ILIKE ${`%${searchTerm}%`} OR customers.name ILIKE ${`%${searchTerm}%`} OR customers.email ILIKE ${`%${searchTerm}%`})
-`;
-  return countRows[0].count;
-}
-
-export async function fetchInvoiceById(id: number | null) {
-  return await sql`SELECT * from INVOICES where id=${id}`;
-}
-
-export async function fetchLatestInvoices() {
-  const latestInvoices = await sql`SELECT * FROM invoices
-    ORDER BY date DESC
-    LIMIT 5;`;
-  return latestInvoices.rows;
-}
diff --git a/dashboard/15-final/app/lib/data.ts b/dashboard/15-final/app/lib/data.ts
new file mode 100644
index 0000000..d757cd9
--- /dev/null
+++ b/dashboard/15-final/app/lib/data.ts
@@ -0,0 +1,132 @@
+import { sql } from '@vercel/postgres';
+import { formatCurrency } from './utils';
+import { Revenue, LatestInvoice } from './definitions';
+
+export async function fetchRevenue(): Promise<Revenue[]> {
+  try {
+    const revenueData = await sql`SELECT * FROM revenue`;
+    return revenueData.rows as Revenue[];
+  } catch (error) {
+    console.error('Failed to fetch revenue data:', error);
+    throw new Error('Failed to fetch revenue data.');
+  }
+}
+
+export async function fetchRevenueDelayed(): Promise<Revenue[]> {
+  try {
+    // We artificially delay a reponse for demo purposes.
+    // Don't do this in real life :)
+    console.log('Fetching revenue data...');
+    await new Promise((resolve) => setTimeout(resolve, 3000));
+
+    const revenueData = await sql`SELECT * FROM revenue`;
+    console.log('Data fetch complete after 3 seconds.');
+
+    return revenueData.rows as Revenue[];
+  } catch (error) {
+    console.error('Failed to fetch revenue data:', error);
+    throw new Error('Failed to fetch revenue data.');
+  }
+}
+
+export async function fetchCounts() {
+  try {
+    const invoiceCount = await sql`SELECT COUNT(*) FROM invoices`;
+    const numberOfInvoices = parseInt(invoiceCount.rows[0].count, 10);
+
+    const customerCount = await sql`SELECT COUNT(*) FROM customers`;
+    const numberOfCustomers = parseInt(customerCount.rows[0].count, 10);
+
+    return { numberOfCustomers, numberOfInvoices };
+  } catch (error) {
+    console.error('Failed to fetch counts:', error);
+    throw new Error('Failed to fetch counts.');
+  }
+}
+
+export async function fetchTotalAmountByStatus() {
+  try {
+    const totalAmount = await sql`SELECT 
+      SUM(CASE WHEN status = 'paid' THEN amount ELSE 0 END) AS "paid",
+      SUM(CASE WHEN status = 'pending' THEN amount ELSE 0 END) AS "pending"
+      FROM invoices`;
+    const totalPaidInvoices = formatCurrency(totalAmount.rows[0].paid);
+    const totalPendingInvoices = formatCurrency(totalAmount.rows[0].pending);
+
+    return { totalPaidInvoices, totalPendingInvoices };
+  } catch (error) {
+    console.error('Failed to fetch total amounts by status:', error);
+    throw new Error('Failed to fetch total amounts by status.');
+  }
+}
+
+export async function fetchLatestInvoices() {
+  try {
+    const data = await sql`
+      SELECT invoices.amount, customers.name, customers.image_url, customers.email 
+      FROM invoices 
+      JOIN customers ON invoices.customer_id = customers.id
+      ORDER BY invoices.date DESC
+      LIMIT 5`;
+    const latestInvoices = data.rows.map((invoice) => ({
+      ...invoice,
+      amount: formatCurrency(invoice.amount),
+    }));
+    return latestInvoices as LatestInvoice[];
+  } catch (error) {
+    console.error('Failed to fetch the latest invoices:', error);
+    throw new Error('Failed to fetch the latest invoices.');
+  }
+}
+
+export async function fetchAllInvoices() {
+  const invoicesData = await sql`SELECT * FROM invoices`;
+  return invoicesData.rows;
+}
+
+export async function fetchAllCustomers() {
+  const customersData = await sql`SELECT * FROM customers`;
+  return customersData.rows;
+}
+
+export async function fetchFilteredInvoices(
+  searchTerm: string,
+  currentPage: number,
+  ITEMS_PER_PAGE: number,
+) {
+  const invoicesData = await sql`
+    SELECT 
+      invoices.*, 
+      customers.name AS customer_name, 
+      customers.email AS customer_email, 
+      customers.image_url AS customer_image
+    FROM 
+      invoices
+    JOIN 
+      customers ON invoices.customer_id = customers.id
+    WHERE 
+      invoices.id::text ILIKE ${`%${searchTerm}%`} OR
+      customers.name ILIKE ${`%${searchTerm}%`} OR
+      customers.email ILIKE ${`%${searchTerm}%`} OR
+      invoices.amount::text ILIKE ${`%${searchTerm}%`} OR
+      invoices.date::text ILIKE ${`%${searchTerm}%`} OR
+      invoices.status ILIKE ${`%${searchTerm}%`}
+    LIMIT ${ITEMS_PER_PAGE}
+    OFFSET ${(currentPage - 1) * ITEMS_PER_PAGE}
+  `;
+  return invoicesData.rows;
+}
+
+export async function fetchInvoiceCountBySearchTerm(searchTerm: string) {
+  const { rows: countRows } = await sql`
+  SELECT COUNT(*) 
+  FROM invoices 
+  LEFT JOIN customers ON invoices.customer_id = customers.id 
+  WHERE (invoices.id::text ILIKE ${`%${searchTerm}%`} OR customers.name ILIKE ${`%${searchTerm}%`} OR customers.email ILIKE ${`%${searchTerm}%`})
+`;
+  return countRows[0].count;
+}
+
+export async function fetchInvoiceById(id: number | null) {
+  return await sql`SELECT * from INVOICES where id=${id}`;
+}
diff --git a/dashboard/15-final/app/lib/definitions.ts b/dashboard/15-final/app/lib/definitions.ts
index bbb5675..84eb7cc 100644
--- a/dashboard/15-final/app/lib/definitions.ts
+++ b/dashboard/15-final/app/lib/definitions.ts
@@ -25,6 +25,14 @@ export type Invoice = {
   date: string;
 };
 
+export type LatestInvoice = {
+  id: number;
+  name: string;
+  image_url: string;
+  email: string;
+  amount: string;
+};
+
 export type Revenue = {
   month: string;
   revenue: number;
diff --git a/dashboard/15-final/app/lib/calculations.ts b/dashboard/15-final/app/lib/utils.ts
similarity index 53%
rename from dashboard/15-final/app/lib/calculations.ts
rename to dashboard/15-final/app/lib/utils.ts
index 2dd143a..3b9582d 100644
--- a/dashboard/15-final/app/lib/calculations.ts
+++ b/dashboard/15-final/app/lib/utils.ts
@@ -1,7 +1,43 @@
-import { Invoice, Revenue } from './definitions';
-import { fetchLatestInvoices } from './data-fetches';
+import { Invoice, Revenue, Customer, LatestInvoice } from './definitions';
 
-export const calculateAllInvoices = (
+export const formatCurrency = (amount: number) => {
+  return (amount / 100).toLocaleString('en-US', {
+    style: 'currency',
+    currency: 'USD',
+  });
+};
+
+export function findLatestInvoices(invoices: Invoice[], customers: Customer[]) {
+  // Sort the invoices by date in descending order and take the top 5
+  const latestInvoices = [...invoices]
+    .sort((a, b) => new Date(b.date).getTime() - new Date(a.date).getTime())
+    .slice(0, 5);
+
+  // Find corresponding customers for the latest 5 invoices
+  const latestInvoicesWithCustomerInfo = latestInvoices.map((invoice) => {
+    const customer = customers.find(
+      (customer) => customer.id === invoice.customer_id,
+    );
+
+    // Format the amount to USD
+    const formattedAmount = invoice.amount.toLocaleString('en-US', {
+      style: 'currency',
+      currency: 'USD',
+    });
+
+    return {
+      id: invoice.id,
+      name: customer?.name,
+      image_url: customer?.image_url,
+      email: customer?.email,
+      amount: formattedAmount,
+    };
+  });
+
+  return latestInvoicesWithCustomerInfo;
+}
+
+export const calculateInvoicesByStatus = (
   invoices: Invoice[],
   status: 'pending' | 'paid',
 ) => {
@@ -29,12 +65,6 @@ export const calculateCustomerInvoices = (
     });
 };
 
-// Once a database is connected, we can use SQL to query the database directly
-// This will be more efficient than querying all invoices and then filtering them
-// E.g. "SELECT * FROM invoices
-// ORDER BY date DESC
-// LIMIT 5;"
-
 export const countCustomerInvoices = (
   invoices: Invoice[],
   customerId: number,
@@ -43,10 +73,6 @@ export const countCustomerInvoices = (
     .length;
 };
 
-export const findLatestInvoices = async () => {
-  return await fetchLatestInvoices();
-};
-
 export const generateYAxis = (revenue: Revenue[]) => {
   // Calculate what labels we need to display on the y-axis
   // based on highest record and in 1000s
diff --git a/dashboard/15-final/app/ui/customers/table.tsx b/dashboard/15-final/app/ui/customers/table.tsx
index af08b5b..a8864ff 100644
--- a/dashboard/15-final/app/ui/customers/table.tsx
+++ b/dashboard/15-final/app/ui/customers/table.tsx
@@ -1,9 +1,9 @@
 import {
   countCustomerInvoices,
   calculateCustomerInvoices,
-} from '@/app/lib/calculations';
+} from '@/app/lib/utils';
 import { Customer, Invoice } from '@/app/lib/definitions';
-import { fetchAllCustomers, fetchAllInvoices } from '@/app/lib/data-fetches';
+import { fetchAllCustomers, fetchAllInvoices } from '@/app/lib/data';
 import Image from 'next/image';
 
 export default async function CustomersTable() {
diff --git a/dashboard/15-final/app/ui/dashboard/latest-invoices.tsx b/dashboard/15-final/app/ui/dashboard/latest-invoices.tsx
index e2c3970..c610ae1 100644
--- a/dashboard/15-final/app/ui/dashboard/latest-invoices.tsx
+++ b/dashboard/15-final/app/ui/dashboard/latest-invoices.tsx
@@ -1,25 +1,16 @@
-// InvoiceList.tsx
-import { Customer, Invoice } from '@/app/lib/definitions';
-import { findLatestInvoices } from '@/app/lib/calculations';
+import { LatestInvoice } from '@/app/lib/definitions';
 import Image from 'next/image';
 
 export default async function LatestInvoices({
-  invoices,
-  customers,
+  latestInvoices,
 }: {
-  invoices: Invoice[];
-  customers: Customer[];
+  latestInvoices: LatestInvoice[];
 }) {
-  const lastFiveInvoices = await findLatestInvoices();
-
   return (
-    <div className="w-full rounded-xl border p-6 shadow-sm md:col-span-4 lg:col-span-3">
+    <div className="w-full rounded-xl border bg-white p-6 shadow-sm md:col-span-4 lg:col-span-3">
       <h2 className="font-semibold">Latest Invoices</h2>
 
-      {lastFiveInvoices.map((invoice) => {
-        const customer = customers.find(
-          (customer) => customer.id === invoice.customer_id,
-        );
+      {latestInvoices.map((invoice) => {
         return (
           <div
             key={invoice.id}
@@ -27,26 +18,23 @@ export default async function LatestInvoices({
           >
             <div className="flex items-center">
               <Image
-                src={customer?.image_url || ''}
-                alt={customer?.name || ''}
+                src={invoice.image_url}
+                alt={invoice.name}
                 className="mr-4 rounded-full"
                 width={32}
                 height={32}
               />
               <div className="min-w-0">
                 <p className="truncate text-sm font-semibold md:text-base">
-                  {customer?.name}
+                  {invoice.name}
                 </p>
                 <p className="hidden text-sm text-gray-500 sm:block">
-                  {customer?.email}
+                  {invoice.email}
                 </p>
               </div>
             </div>
             <p className="truncate text-sm font-medium md:text-base">
-              {(invoice.amount / 100).toLocaleString('en-US', {
-                style: 'currency',
-                currency: 'USD',
-              })}
+              {invoice.amount}
             </p>
           </div>
         );
diff --git a/dashboard/15-final/app/ui/dashboard/overview.tsx b/dashboard/15-final/app/ui/dashboard/overview.tsx
deleted file mode 100644
index 32e39dc..0000000
--- a/dashboard/15-final/app/ui/dashboard/overview.tsx
+++ /dev/null
@@ -1,40 +0,0 @@
-import Card from '@/app/ui/dashboard/card';
-import { calculateAllInvoices } from '@/app/lib/calculations';
-import RevenueChart from '@/app/ui/dashboard/revenue-chart';
-import LatestInvoices from '@/app/ui/dashboard/latest-invoices';
-import { Customer, Invoice, Revenue } from '@/app/lib/definitions';
-import {
-  fetchAllCustomers,
-  fetchAllInvoices,
-  fetchAllRevenue,
-} from '@/app/lib/data-fetches';
-
-export default async function DashboardOverview() {
-  const invoices = (await fetchAllInvoices()) as Invoice[];
-  const customers = (await fetchAllCustomers()) as Customer[];
-  const revenue = (await fetchAllRevenue()) as Revenue[];
-
-  const totalPaidInvoices = calculateAllInvoices(invoices, 'paid');
-  const totalPendingInvoices = calculateAllInvoices(invoices, 'pending');
-  const numberOfInvoices = invoices.length;
-  const numberOfCustomers = customers.length;
-
-  return (
-    <>
-      <div className="grid gap-6 sm:grid-cols-2 lg:grid-cols-4">
-        <Card title="Collected" value={totalPaidInvoices} type="collected" />
-        <Card title="Pending" value={totalPendingInvoices} type="pending" />
-        <Card title="Total Invoices" value={numberOfInvoices} type="invoices" />
-        <Card
-          title="Total Customers"
-          value={numberOfCustomers}
-          type="customers"
-        />
-      </div>
-      <div className="mt-6 grid grid-cols-1 gap-6 md:grid-cols-4 lg:grid-cols-8">
-        <RevenueChart revenue={revenue} />
-        <LatestInvoices invoices={invoices} customers={customers} />
-      </div>
-    </>
-  );
-}
diff --git a/dashboard/15-final/app/ui/dashboard/revenue-chart.tsx b/dashboard/15-final/app/ui/dashboard/revenue-chart.tsx
index 5e8798c..9a3100b 100644
--- a/dashboard/15-final/app/ui/dashboard/revenue-chart.tsx
+++ b/dashboard/15-final/app/ui/dashboard/revenue-chart.tsx
@@ -1,12 +1,15 @@
-import { Revenue } from '@/app/lib/definitions';
-import { generateYAxis } from '@/app/lib/calculations';
+import { generateYAxis } from '@/app/lib/utils';
+import { fetchRevenueDelayed } from '@/app/lib/data';
 
 // This component is representational only.
 // For data visualization UI, check out:
+// https://www.tremor.so/
 // https://www.chartjs.org/
 // https://airbnb.io/visx/
-// https://www.tremor.so/
-export default function RevenueChart({ revenue }: { revenue: Revenue[] }) {
+
+export default async function RevenueChart() {
+  const revenue = await fetchRevenueDelayed();
+
   const chartHeight = 350;
   const { yAxisLabels, topLabel } = generateYAxis(revenue);
 
@@ -15,7 +18,7 @@ export default function RevenueChart({ revenue }: { revenue: Revenue[] }) {
   }
 
   return (
-    <div className="rounded-xl border p-6 shadow-sm md:col-span-5">
+    <div className="rounded-xl border bg-white p-6 shadow-sm md:col-span-5">
       <h2 className="font-semibold">Revenue</h2>
       <div className="sm:grid-cols-13 mt-4 grid grid-cols-12 items-end gap-2 md:gap-4">
         {/* y-axis */}
diff --git a/dashboard/15-final/app/ui/invoices/table.tsx b/dashboard/15-final/app/ui/invoices/table.tsx
index b10c711..63f25da 100644
--- a/dashboard/15-final/app/ui/invoices/table.tsx
+++ b/dashboard/15-final/app/ui/invoices/table.tsx
@@ -11,7 +11,7 @@ import PaginationButtons from './pagination';
 import {
   fetchFilteredInvoices,
   fetchInvoiceCountBySearchTerm,
-} from '@/app/lib/data-fetches';
+} from '@/app/lib/data';
 
 const ITEMS_PER_PAGE = 10;
 
diff --git a/dashboard/15-final/app/ui/skeletons.tsx b/dashboard/15-final/app/ui/skeletons.tsx
new file mode 100644
index 0000000..48a9508
--- /dev/null
+++ b/dashboard/15-final/app/ui/skeletons.tsx
@@ -0,0 +1,90 @@
+// Loading animation
+const shimmer =
+  'before:absolute before:inset-0 before:-translate-x-full before:animate-[shimmer_2s_infinite] before:bg-gradient-to-r before:from-transparent before:via-white/60 before:to-transparent';
+
+export function CardSkeleton() {
+  return (
+    <div
+      className={`${shimmer} relative h-[114px] overflow-hidden rounded-xl border bg-white p-6 shadow-sm`}
+    >
+      <div className="flex justify-between">
+        <div className="h-6 w-20 rounded-lg bg-gray-100"></div>
+        <div className="h-6 w-6 rounded-lg bg-gray-100"></div>
+      </div>
+      <div className="mt-4 h-8 w-1/2 rounded-lg bg-gray-100"></div>
+    </div>
+  );
+}
+
+export function RevenueChartSkeleton() {
+  return (
+    <div
+      className={`${shimmer} relative h-[464px] overflow-hidden rounded-xl border bg-white p-6 shadow-sm md:col-span-5`}
+    >
+      <div className="h-8 w-32 rounded-lg bg-gray-100"></div>
+      <div className="my-4 h-[370px] w-full rounded-lg bg-gray-100"></div>
+    </div>
+  );
+}
+
+export function LatestInvoicesSkeleton() {
+  return (
+    <div
+      className={`${shimmer} relative w-full  overflow-hidden rounded-xl border bg-white p-6 shadow-sm md:col-span-4 lg:col-span-3`}
+    >
+      <div className="h-8 w-40 rounded-lg bg-gray-100"></div>
+      <div className="mt-8 flex flex-row items-center justify-between">
+        <div className="flex items-center">
+          <div className="h-10 w-10 rounded-lg bg-gray-100"></div>
+          <div className="ml-4 h-10 w-44 rounded-lg bg-gray-100"></div>
+        </div>
+        <div className="h-10 w-16 rounded-lg bg-gray-100"></div>
+      </div>
+      <div className="mt-8 flex flex-row items-center justify-between">
+        <div className="flex items-center">
+          <div className="h-10 w-10 rounded-lg bg-gray-100"></div>
+          <div className="ml-4 h-10 w-44 rounded-lg bg-gray-100"></div>
+        </div>
+        <div className="h-10 w-16 rounded-lg bg-gray-100"></div>
+      </div>
+      <div className="mt-8 flex flex-row items-center justify-between">
+        <div className="flex items-center">
+          <div className="h-10 w-10 rounded-lg bg-gray-100"></div>
+          <div className="ml-4 h-10 w-44 rounded-lg bg-gray-100"></div>
+        </div>
+        <div className="h-10 w-16 rounded-lg bg-gray-100"></div>
+      </div>
+      <div className="mt-8 flex flex-row items-center justify-between">
+        <div className="flex items-center">
+          <div className="h-10 w-10 rounded-lg bg-gray-100"></div>
+          <div className="ml-4 h-10 w-44 rounded-lg bg-gray-100"></div>
+        </div>
+        <div className="h-10 w-16 rounded-lg bg-gray-100"></div>
+      </div>
+      <div className="mt-8 flex flex-row items-center justify-between">
+        <div className="flex items-center">
+          <div className="h-10 w-10 rounded-lg bg-gray-100"></div>
+          <div className="ml-4 h-10 w-44 rounded-lg bg-gray-100"></div>
+        </div>
+        <div className="h-10 w-16 rounded-lg bg-gray-100"></div>
+      </div>
+    </div>
+  );
+}
+
+export default function DashboardSkeleton() {
+  return (
+    <>
+      <div className="grid gap-6 sm:grid-cols-2 lg:grid-cols-4">
+        <CardSkeleton />
+        <CardSkeleton />
+        <CardSkeleton />
+        <CardSkeleton />
+      </div>
+      <div className="mt-6 grid grid-cols-1 gap-6 md:grid-cols-4 lg:grid-cols-8">
+        <RevenueChartSkeleton />
+        <LatestInvoicesSkeleton />
+      </div>
+    </>
+  );
+}
diff --git a/dashboard/15-final/tailwind.config.ts b/dashboard/15-final/tailwind.config.ts
index 1e343b0..aec8276 100644
--- a/dashboard/15-final/tailwind.config.ts
+++ b/dashboard/15-final/tailwind.config.ts
@@ -12,7 +12,15 @@ const config: Config = {
         '13': 'repeat(13, minmax(0, 1fr))',
       },
     },
+    keyframes: {
+      shimmer: {
+        '100%': {
+          transform: 'translateX(100%)',
+        },
+      },
+    },
   },
+
   plugins: [require('@tailwindcss/forms')],
 };
 export default config;