Page Layer

Page Layer Skill

Scope

• app/**/page.tsx - Next.js page components
• app/**/layout.tsx - Layout components
• app/**/not-found.tsx - Not found pages
• app/**/loading.tsx - Loading states
• app/**/error.tsx - Error boundaries

Decision Tree

Creating a new page?

1. Determine route: Map URL to folder structure in app/
2. Create folder: app/[route-name]/
3. Create page.tsx: Export default async function
4. Add metadata: Export metadata object or generateMetadata function
5. Use layout components: Container, PageIntro, etc.

Creating a dynamic route?

1. Create folder with brackets: app/[param]/ or app/[...slug]/
2. Type params as Promise: params: Promise<{ param: string }>
3. Await params: const { param } = await params;
4. Add generateStaticParams: For static generation
5. Add generateMetadata: For dynamic meta tags

Adding page metadata?

1. Static metadata: Export metadata object
2. Dynamic metadata: Export async generateMetadata function
3. Include OpenGraph: title, description, images, type
4. Use env variables: env.PROJECT_BASE_TITLE, etc.

Adding a layout?

1. Create layout.tsx in route folder
2. Accept children prop
3. Wrap with structural components
4. Export metadata if needed (inherited by child pages)

Quick Templates

Basic Page

import type { Metadata } from "next";
import { Container } from "@/components/layout/container";
import { PageIntro } from "@/components/layout/page-intro";

export const metadata: Metadata = {
  title: "Page Title",
  description: "Page description for SEO",
};

export default function PageName() {
  return (
    <Container className="mt-16">
      <PageIntro title="Page Title">
        <p>Page content description</p>
      </PageIntro>
      {/* Page content */}
    </Container>
  );
}

Dynamic Route Page (Next.js 15)

import type { Metadata } from "next";
import { notFound } from "next/navigation";

type Props = {
  params: Promise<{ slug: string }>;
};

export async function generateStaticParams() {
  // Return array of param objects for static generation
  return [{ slug: "example-1" }, { slug: "example-2" }];
}

export async function generateMetadata({ params }: Props): Promise<Metadata> {
  const { slug } = await params;
  // Fetch data and return metadata
  return {
    title: `Dynamic Title for ${slug}`,
    description: "Dynamic description",
  };
}

export default async function Page({ params }: Props) {
  const { slug } = await params;

  // Fetch data
  const data = getData(slug);
  if (!data) {
    notFound();
  }

  return (
    <div>
      <h1>{data.title}</h1>
    </div>
  );
}

Layout

import type { Metadata } from "next";

export const metadata: Metadata = {
  title: {
    template: "%s | Section Name",
    default: "Section Name",
  },
};

export default function SectionLayout({
  children,
}: {
  children: React.ReactNode;
}) {
  return (
    <div className="section-wrapper">
      {children}
    </div>
  );
}

Not Found Page

import { NotFound } from "@/components/shared/not-found";

export default function NotFoundPage() {
  return <NotFound message="Page not found" />;
}

Metadata with OpenGraph

import type { Metadata } from "next";
import { getCldImageUrl } from "next-cloudinary";
import { env } from "@/lib/config/env";
import { withCloudinaryCloudName } from "@/lib/utils/withCloudinaryCloudName";

const ogImageUrl = getCldImageUrl({
  width: 1200,
  height: 630,
  src: withCloudinaryCloudName("path/to/image"),
});

export const metadata: Metadata = {
  title: "Page Title",
  description: "Page description",
  openGraph: {
    title: "Page Title",
    description: "Page description",
    url: "/page-path",
    images: [ogImageUrl],
    type: "website",
    locale: "en_GB",
    siteName: env.PROJECT_BASE_TITLE,
  },
};

Mistakes

• ❌ Missing await params in Next.js 15 (params is now a Promise)
• ❌ "use client" on pages (should be server components)
• ❌ Missing generateStaticParams for dynamic routes (breaks static export)
• ❌ Not calling notFound() for missing data
• ❌ Hardcoding URLs instead of using route config
• ❌ Missing metadata/OpenGraph tags

Validation

After changes, run:

.claude/skills/page-layer/scripts/validate-page-patterns.sh <file>
pnpm build      # Full build validates routes
pnpm typecheck  # TypeScript validation

Route Structure

app/
├── layout.tsx              # Root layout (required)
├── page.tsx                # Home page (/)
├── not-found.tsx           # Global 404
├── about/
│   └── page.tsx            # /about
├── articles/
│   ├── page.tsx            # /articles
│   └── [slug]/
│       ├── page.tsx        # /articles/[slug]
│       └── not-found.tsx   # Article 404
├── contact/
│   └── page.tsx            # /contact
└── projects/
    └── page.tsx            # /projects

Next.js 15 Breaking Changes

Params are now Promises:

// Next.js 14 (old)
export default function Page({ params }: { params: { slug: string } }) {
  const { slug } = params;
}

// Next.js 15 (current)
export default async function Page({ params }: { params: Promise<{ slug: string }> }) {
  const { slug } = await params;
}