Layout Setup

Create a shared layout with header and footer that wraps all pages.

Create the Layout Component

Create src/js/layouts/MainLayout/MainLayout.js:

import React from "react";
import { Outlet, split } from "catalyst-core";
import Header from "../../components/Header/Header";


// Lazy load the Footer component
const Footer = split(() => import("../../components/Footer/Footer"), {
  fallback: <div>Loading footer...</div>,
  ssr: false,
});


const MainLayout = () => {
  return (
    <div>
      <Header />
      <main>
        <Outlet />
      </main>
      <Footer />
    </div>
  );
};


export default MainLayout;

The <Outlet /> component renders the matched child route.

Create the Header Component

Create src/js/components/Header/Header.js:

import React from "react";
import { Link } from "catalyst-core";


const Header = () => {
  return (
    <header className="header">
      <div className="header-brand">
        <img src="/assets/dog-logo.png" alt="Logo" className="header-logo" />
        <h1>Dog Adoption Center</h1>
      </div>
      <nav>
        <Link to="/" className="nav-link">Home</Link>
        <Link to="/about" className="nav-link">About</Link>
      </nav>
    </header>
  );
};


export default Header;

Create src/js/components/Footer/Footer.js:

import React from "react";


const Footer = () => {
  return (
    <footer className="footer">
      <p>© 2026 Dog Adoption Center</p>
      <p>
        Data from <a href="https://dog.ceo/dog-api/">Dog API</a>
      </p>
    </footer>
  );
};


export default Footer;

Create an About Page

Create src/js/pages/About/About.js:

import React from "react";


const About = () => {
  return (
    <div className="container">
      <h1>About</h1>
      <p>A demo application built with Catalyst.</p>
    </div>
  );
};


export default About;

Update Routes

Update src/js/routes/index.js to use the layout:

import MainLayout from "../layouts/MainLayout/MainLayout";
import Home from "../pages/Home/Home";
import BreedDetails from "../pages/BreedDetails/BreedDetails";
import About from "../pages/About/About";


const routes = [
  {
    path: "/",
    component: MainLayout,
    children: [
      {
        path: "",
        index: true,
        component: Home,
      },
      {
        path: "breed/:breed",
        component: BreedDetails,
      },
      {
        path: "about",
        component: About,
      },
    ],
  },
];


export default routes;

All pages now share the header and footer. Next, we'll set up static asset loading.